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diff --git a/doc/bashref.html b/doc/bashref.html new file mode 100644 index 0000000..d36b72b --- /dev/null +++ b/doc/bashref.html @@ -0,0 +1,16225 @@ +<HTML> +<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> +<!-- Created on December, 29 2009 by texi2html 1.64 --> +<!-- +Written by: Lionel Cons <Lionel.Cons@cern.ch> (original author) + Karl Berry <karl@freefriends.org> + Olaf Bachmann <obachman@mathematik.uni-kl.de> + and many others. +Maintained by: Olaf Bachmann <obachman@mathematik.uni-kl.de> +Send bugs and suggestions to <texi2html@mathematik.uni-kl.de> + +--> +<HEAD> +<TITLE>Bash Reference Manual: </TITLE> + +<META NAME="description" CONTENT="Bash Reference Manual: "> +<META NAME="keywords" CONTENT="Bash Reference Manual: "> +<META NAME="resource-type" CONTENT="document"> +<META NAME="distribution" CONTENT="global"> +<META NAME="Generator" CONTENT="texi2html 1.64"> + +</HEAD> + +<BODY LANG="" BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#0000FF" VLINK="#800080" ALINK="#FF0000"> + +<A NAME="SEC_Top"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H1>Bash Reference Manual</H1></P><P> + +This text is a brief description of the features that are present in +the Bash shell (version 4.1, 23 December 2009). +</P><P> + +This is Edition 4.1, last updated 23 December 2009, +of <CITE>The GNU Bash Reference Manual</CITE>, +for <CODE>Bash</CODE>, Version 4.1. +</P><P> + +Bash contains features that appear in other popular shells, and some +features that only appear in Bash. Some of the shells that Bash has +borrowed concepts from are the Bourne Shell (<TT>`sh'</TT>), the Korn Shell +(<TT>`ksh'</TT>), and the C-shell (<TT>`csh'</TT> and its successor, +<TT>`tcsh'</TT>). The following menu breaks the features up into +categories based upon which one of these other shells inspired the +feature. +</P><P> + +This manual is meant as a brief introduction to features found in +Bash. The Bash manual page should be used as the definitive +reference on shell behavior. +</P><P> + +<BLOCKQUOTE><TABLE BORDER=0 CELLSPACING=0> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC1">1. Introduction</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">An introduction to the shell.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC4">2. Definitions</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Some definitions used in the rest of this + manual.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC5">3. Basic Shell Features</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">The shell "building blocks".</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC58">4. Shell Builtin Commands</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Commands that are a part of the shell.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC65">5. Shell Variables</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Variables used or set by Bash.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC68">6. Bash Features</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Features found only in Bash.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC91">7. Job Control</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">What job control is and how Bash allows you + to use it.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC95">8. Command Line Editing</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Chapter describing the command line + editing features.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC119">9. Using History Interactively</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Command History Expansion</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC126">10. Installing Bash</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">How to build and install Bash on your system.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC135">A. Reporting Bugs</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">How to report bugs in Bash.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC136">B. Major Differences From The Bourne Shell</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">A terse list of the differences + between Bash and historical + versions of /bin/sh.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC138">C. GNU Free Documentation License</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Copying and sharing this documentation.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC140">D. Indexes</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Various indexes for this manual.</TD></TR> +</TABLE></BLOCKQUOTE> +<P> + +<HR SIZE=1> +<A NAME="SEC1"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC2"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[ << ]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC4"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<A NAME="Introduction"></A> +<H1> 1. Introduction </H1> +<!--docid::SEC1::--> +<BLOCKQUOTE><TABLE BORDER=0 CELLSPACING=0> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC2">1.1 What is Bash?</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">A short description of Bash.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC3">1.2 What is a shell?</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">A brief introduction to shells.</TD></TR> +</TABLE></BLOCKQUOTE> +<P> + +<A NAME="What is Bash?"></A> +<HR SIZE="6"> +<A NAME="SEC2"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC1"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC3"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[ << ]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC1"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC4"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H2> 1.1 What is Bash? </H2> +<!--docid::SEC2::--> +<P> + +Bash is the shell, or command language interpreter, +for the GNU operating system. +The name is an acronym for the <SAMP>`Bourne-Again SHell'</SAMP>, +a pun on Stephen Bourne, the author of the direct ancestor of +the current Unix shell <CODE>sh</CODE>, +which appeared in the Seventh Edition Bell Labs Research version +of Unix. +</P><P> + +Bash is largely compatible with <CODE>sh</CODE> and incorporates useful +features from the Korn shell <CODE>ksh</CODE> and the C shell <CODE>csh</CODE>. +It is intended to be a conformant implementation of the IEEE +POSIX Shell and Tools portion of the IEEE POSIX +specification (IEEE Standard 1003.1). +It offers functional improvements over <CODE>sh</CODE> for both interactive and +programming use. +</P><P> + +While the GNU operating system provides other shells, including +a version of <CODE>csh</CODE>, Bash is the default shell. +Like other GNU software, Bash is quite portable. It currently runs +on nearly every version of Unix and a few other operating systems - +independently-supported ports exist for MS-DOS, OS/2, +and Windows platforms. +</P><P> + +<A NAME="What is a shell?"></A> +<HR SIZE="6"> +<A NAME="SEC3"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC2"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC4"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[ << ]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC1"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC4"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H2> 1.2 What is a shell? </H2> +<!--docid::SEC3::--> +<P> + +At its base, a shell is simply a macro processor that executes +commands. The term macro processor means functionality where text +and symbols are expanded to create larger expressions. +</P><P> + +A Unix shell is both a command interpreter and a programming +language. As a command interpreter, the shell provides the user +interface to the rich set of GNU utilities. The programming +language features allow these utilities to be combined. +Files containing commands can be created, and become +commands themselves. These new commands have the same status as +system commands in directories such as <TT>`/bin'</TT>, allowing users +or groups to establish custom environments to automate their common +tasks. +</P><P> + +Shells may be used interactively or non-interactively. In +interactive mode, they accept input typed from the keyboard. +When executing non-interactively, shells execute commands read +from a file. +</P><P> + +A shell allows execution of GNU commands, both synchronously and +asynchronously. +The shell waits for synchronous commands to complete before accepting +more input; asynchronous commands continue to execute in parallel +with the shell while it reads and executes additional commands. +The <EM>redirection</EM> constructs permit +fine-grained control of the input and output of those commands. +Moreover, the shell allows control over the contents of commands' +environments. +</P><P> + +Shells also provide a small set of built-in +commands (<EM>builtins</EM>) implementing functionality impossible +or inconvenient to obtain via separate utilities. +For example, <CODE>cd</CODE>, <CODE>break</CODE>, <CODE>continue</CODE>, and +<CODE>exec</CODE>) cannot be implemented outside of the shell because +they directly manipulate the shell itself. +The <CODE>history</CODE>, <CODE>getopts</CODE>, <CODE>kill</CODE>, or <CODE>pwd</CODE> +builtins, among others, could be implemented in separate utilities, +but they are more convenient to use as builtin commands. +All of the shell builtins are described in +subsequent sections. +</P><P> + +While executing commands is essential, most of the power (and +complexity) of shells is due to their embedded programming +languages. Like any high-level language, the shell provides +variables, flow control constructs, quoting, and functions. +</P><P> + +Shells offer features geared specifically for +interactive use rather than to augment the programming language. +These interactive features include job control, command line +editing, command history and aliases. Each of these features is +described in this manual. +</P><P> + +<A NAME="Definitions"></A> +<HR SIZE="6"> +<A NAME="SEC4"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC3"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC5"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC5"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC5"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H1> 2. Definitions </H1> +<!--docid::SEC4::--> +These definitions are used throughout the remainder of this manual. +<P> + +<DL COMPACT> + +<DT><CODE>POSIX</CODE> +<DD><A NAME="IDX1"></A> +A family of open system standards based on Unix. Bash +is primarily concerned with the Shell and Utilities portion of the +POSIX 1003.1 standard. +<P> + +<DT><CODE>blank</CODE> +<DD>A space or tab character. +<P> + +<DT><CODE>builtin</CODE> +<DD><A NAME="IDX2"></A> +A command that is implemented internally by the shell itself, rather +than by an executable program somewhere in the file system. +<P> + +<DT><CODE>control operator</CODE> +<DD><A NAME="IDX3"></A> +A <CODE>token</CODE> that performs a control function. It is a <CODE>newline</CODE> +or one of the following: +<SAMP>`||'</SAMP>, <SAMP>`&&'</SAMP>, <SAMP>`&'</SAMP>, <SAMP>`;'</SAMP>, <SAMP>`;;'</SAMP>, +<SAMP>`|'</SAMP>, <SAMP>`|&'</SAMP>, <SAMP>`('</SAMP>, or <SAMP>`)'</SAMP>. +<P> + +<DT><CODE>exit status</CODE> +<DD><A NAME="IDX4"></A> +The value returned by a command to its caller. The value is restricted +to eight bits, so the maximum value is 255. +<P> + +<DT><CODE>field</CODE> +<DD><A NAME="IDX5"></A> +A unit of text that is the result of one of the shell expansions. After +expansion, when executing a command, the resulting fields are used as +the command name and arguments. +<P> + +<DT><CODE>filename</CODE> +<DD><A NAME="IDX6"></A> +A string of characters used to identify a file. +<P> + +<DT><CODE>job</CODE> +<DD><A NAME="IDX7"></A> +A set of processes comprising a pipeline, and any processes descended +from it, that are all in the same process group. +<P> + +<DT><CODE>job control</CODE> +<DD><A NAME="IDX8"></A> +A mechanism by which users can selectively stop (suspend) and restart +(resume) execution of processes. +<P> + +<DT><CODE>metacharacter</CODE> +<DD><A NAME="IDX9"></A> +A character that, when unquoted, separates words. A metacharacter is +a <CODE>blank</CODE> or one of the following characters: +<SAMP>`|'</SAMP>, <SAMP>`&'</SAMP>, <SAMP>`;'</SAMP>, <SAMP>`('</SAMP>, <SAMP>`)'</SAMP>, <SAMP>`<'</SAMP>, or +<SAMP>`>'</SAMP>. +<P> + +<DT><CODE>name</CODE> +<DD><A NAME="IDX10"></A> +<A NAME="IDX11"></A> +A <CODE>word</CODE> consisting solely of letters, numbers, and underscores, +and beginning with a letter or underscore. <CODE>Name</CODE>s are used as +shell variable and function names. +Also referred to as an <CODE>identifier</CODE>. +<P> + +<DT><CODE>operator</CODE> +<DD><A NAME="IDX12"></A> +A <CODE>control operator</CODE> or a <CODE>redirection operator</CODE>. +See section <A HREF="bashref.html#SEC39">3.6 Redirections</A>, for a list of redirection operators. +Operators contain at least one unquoted <CODE>metacharacter</CODE>. +<P> + +<DT><CODE>process group</CODE> +<DD><A NAME="IDX13"></A> +A collection of related processes each having the same process +group ID. +<P> + +<DT><CODE>process group ID</CODE> +<DD><A NAME="IDX14"></A> +A unique identifier that represents a <CODE>process group</CODE> +during its lifetime. +<P> + +<DT><CODE>reserved word</CODE> +<DD><A NAME="IDX15"></A> +A <CODE>word</CODE> that has a special meaning to the shell. Most reserved +words introduce shell flow control constructs, such as <CODE>for</CODE> and +<CODE>while</CODE>. +<P> + +<DT><CODE>return status</CODE> +<DD><A NAME="IDX16"></A> +A synonym for <CODE>exit status</CODE>. +<P> + +<DT><CODE>signal</CODE> +<DD><A NAME="IDX17"></A> +A mechanism by which a process may be notified by the kernel +of an event occurring in the system. +<P> + +<DT><CODE>special builtin</CODE> +<DD><A NAME="IDX18"></A> +A shell builtin command that has been classified as special by the +POSIX standard. +<P> + +<DT><CODE>token</CODE> +<DD><A NAME="IDX19"></A> +A sequence of characters considered a single unit by the shell. +It is either a <CODE>word</CODE> or an <CODE>operator</CODE>. +<P> + +<DT><CODE>word</CODE> +<DD><A NAME="IDX20"></A> +A sequence of characters treated as a unit by the shell. +Words may not include unquoted <CODE>metacharacters</CODE>. +</DL> +<P> + +<A NAME="Basic Shell Features"></A> +<HR SIZE="6"> +<A NAME="SEC5"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC4"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC6"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC58"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC58"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H1> 3. Basic Shell Features </H1> +<!--docid::SEC5::--> +<P> + +Bash is an acronym for <SAMP>`Bourne-Again SHell'</SAMP>. +The Bourne shell is +the traditional Unix shell originally written by Stephen Bourne. +All of the Bourne shell builtin commands are available in Bash, +The rules for evaluation and quoting are taken from the POSIX +specification for the `standard' Unix shell. +</P><P> + +This chapter briefly summarizes the shell's `building blocks': +commands, control structures, shell functions, shell <I>parameters</I>, +shell expansions, +<I>redirections</I>, which are a way to direct input and output from +and to named files, and how the shell executes commands. +</P><P> + +<BLOCKQUOTE><TABLE BORDER=0 CELLSPACING=0> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC6">3.1 Shell Syntax</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">What your input means to the shell.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC15">3.2 Shell Commands</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">The types of commands you can use.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC24">3.3 Shell Functions</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Grouping commands by name.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC25">3.4 Shell Parameters</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">How the shell stores values.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC28">3.5 Shell Expansions</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">How Bash expands parameters and the various + expansions available.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC39">3.6 Redirections</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">A way to control where input and output go.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC50">3.7 Executing Commands</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">What happens when you run a command.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC57">3.8 Shell Scripts</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Executing files of shell commands.</TD></TR> +</TABLE></BLOCKQUOTE> +<P> + +<A NAME="Shell Syntax"></A> +<HR SIZE="6"> +<A NAME="SEC6"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC5"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC7"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC5"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC5"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC15"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H2> 3.1 Shell Syntax </H2> +<!--docid::SEC6::--> +<BLOCKQUOTE><TABLE BORDER=0 CELLSPACING=0> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC7">3.1.1 Shell Operation</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">The basic operation of the shell.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC8">3.1.2 Quoting</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">How to remove the special meaning from characters.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC14">3.1.3 Comments</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">How to specify comments.</TD></TR> +</TABLE></BLOCKQUOTE> +<P> + +When the shell reads input, it proceeds through a +sequence of operations. If the input indicates the beginning of a +comment, the shell ignores the comment symbol (<SAMP>`#'</SAMP>), and the rest +of that line. + +Otherwise, roughly speaking, the shell reads its input and +divides the input into words and operators, employing the quoting rules +to select which meanings to assign various words and characters. +</P><P> + +The shell then parses these tokens into commands and other constructs, +removes the special meaning of certain words or characters, expands +others, redirects input and output as needed, executes the specified +command, waits for the command's exit status, and makes that exit status +available for further inspection or processing. +</P><P> + +<A NAME="Shell Operation"></A> +<HR SIZE="6"> +<A NAME="SEC7"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC6"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC8"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC5"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC6"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC15"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 3.1.1 Shell Operation </H3> +<!--docid::SEC7::--> +<P> + +The following is a brief description of the shell's operation when it +reads and executes a command. Basically, the shell does the +following: +</P><P> + +<OL> +<LI> +Reads its input from a file (see section <A HREF="bashref.html#SEC57">3.8 Shell Scripts</A>), from a string +supplied as an argument to the <SAMP>`-c'</SAMP> invocation option +(see section <A HREF="bashref.html#SEC69">6.1 Invoking Bash</A>), or from the user's terminal. +<P> + +<LI> +Breaks the input into words and operators, obeying the quoting rules +described in <A HREF="bashref.html#SEC8">3.1.2 Quoting</A>. These tokens are separated by +<CODE>metacharacters</CODE>. Alias expansion is performed by this step +(see section <A HREF="bashref.html#SEC84">6.6 Aliases</A>). +<P> + +<LI> +Parses the tokens into simple and compound commands +(see section <A HREF="bashref.html#SEC15">3.2 Shell Commands</A>). +<P> + +<LI> +Performs the various shell expansions (see section <A HREF="bashref.html#SEC28">3.5 Shell Expansions</A>), breaking +the expanded tokens into lists of filenames (see section <A HREF="bashref.html#SEC36">3.5.8 Filename Expansion</A>) +and commands and arguments. +<P> + +<LI> +Performs any necessary redirections (see section <A HREF="bashref.html#SEC39">3.6 Redirections</A>) and removes +the redirection operators and their operands from the argument list. +<P> + +<LI> +Executes the command (see section <A HREF="bashref.html#SEC50">3.7 Executing Commands</A>). +<P> + +<LI> +Optionally waits for the command to complete and collects its exit +status (see section <A HREF="bashref.html#SEC55">3.7.5 Exit Status</A>). +<P> + +</OL> +<P> + +<A NAME="Quoting"></A> +<HR SIZE="6"> +<A NAME="SEC8"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC7"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC9"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC14"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC6"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC14"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 3.1.2 Quoting </H3> +<!--docid::SEC8::--> +<BLOCKQUOTE><TABLE BORDER=0 CELLSPACING=0> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC9">3.1.2.1 Escape Character</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">How to remove the special meaning from a single + character.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC10">3.1.2.2 Single Quotes</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">How to inhibit all interpretation of a sequence + of characters.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC11">3.1.2.3 Double Quotes</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">How to suppress most of the interpretation of a + sequence of characters.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC12">3.1.2.4 ANSI-C Quoting</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">How to expand ANSI-C sequences in quoted strings.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC13">3.1.2.5 Locale-Specific Translation</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">How to translate strings into different languages.</TD></TR> +</TABLE></BLOCKQUOTE> +<P> + +Quoting is used to remove the special meaning of certain +characters or words to the shell. Quoting can be used to +disable special treatment for special characters, to prevent +reserved words from being recognized as such, and to prevent +parameter expansion. +</P><P> + +Each of the shell metacharacters (see section <A HREF="bashref.html#SEC4">2. Definitions</A>) +has special meaning to the shell and must be quoted if it is to +represent itself. +When the command history expansion facilities are being used +(see section <A HREF="bashref.html#SEC122">9.3 History Expansion</A>), the +<VAR>history expansion</VAR> character, usually <SAMP>`!'</SAMP>, must be quoted +to prevent history expansion. See section <A HREF="bashref.html#SEC120">9.1 Bash History Facilities</A>, for +more details concerning history expansion. +</P><P> + +There are three quoting mechanisms: the +<VAR>escape character</VAR>, single quotes, and double quotes. +</P><P> + +<A NAME="Escape Character"></A> +<HR SIZE="6"> +<A NAME="SEC9"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC8"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC10"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC14"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC8"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC14"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H4> 3.1.2.1 Escape Character </H4> +<!--docid::SEC9::--> +A non-quoted backslash <SAMP>`\'</SAMP> is the Bash escape character. +It preserves the literal value of the next character that follows, +with the exception of <CODE>newline</CODE>. If a <CODE>\newline</CODE> pair +appears, and the backslash itself is not quoted, the <CODE>\newline</CODE> +is treated as a line continuation (that is, it is removed from +the input stream and effectively ignored). +<P> + +<A NAME="Single Quotes"></A> +<HR SIZE="6"> +<A NAME="SEC10"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC9"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC11"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC11"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC8"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC14"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H4> 3.1.2.2 Single Quotes </H4> +<!--docid::SEC10::--> +<P> + +Enclosing characters in single quotes (<SAMP>`''</SAMP>) preserves the literal value +of each character within the quotes. A single quote may not occur +between single quotes, even when preceded by a backslash. +</P><P> + +<A NAME="Double Quotes"></A> +<HR SIZE="6"> +<A NAME="SEC11"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC10"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC12"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC12"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC8"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC14"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H4> 3.1.2.3 Double Quotes </H4> +<!--docid::SEC11::--> +<P> + +Enclosing characters in double quotes (<SAMP>`"'</SAMP>) preserves the literal value +of all characters within the quotes, with the exception of +<SAMP>`$'</SAMP>, <SAMP>``'</SAMP>, <SAMP>`\'</SAMP>, +and, when history expansion is enabled, <SAMP>`!'</SAMP>. +The characters <SAMP>`$'</SAMP> and <SAMP>``'</SAMP> +retain their special meaning within double quotes (see section <A HREF="bashref.html#SEC28">3.5 Shell Expansions</A>). +The backslash retains its special meaning only when followed by one of +the following characters: +<SAMP>`$'</SAMP>, <SAMP>``'</SAMP>, <SAMP>`"'</SAMP>, <SAMP>`\'</SAMP>, or <CODE>newline</CODE>. +Within double quotes, backslashes that are followed by one of these +characters are removed. Backslashes preceding characters without a +special meaning are left unmodified. +A double quote may be quoted within double quotes by preceding it with +a backslash. +If enabled, history expansion will be performed unless an <SAMP>`!'</SAMP> +appearing in double quotes is escaped using a backslash. +The backslash preceding the <SAMP>`!'</SAMP> is not removed. +</P><P> + +The special parameters <SAMP>`*'</SAMP> and <SAMP>`@'</SAMP> have special meaning +when in double quotes (see section <A HREF="bashref.html#SEC31">3.5.3 Shell Parameter Expansion</A>). +</P><P> + +<A NAME="ANSI-C Quoting"></A> +<HR SIZE="6"> +<A NAME="SEC12"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC11"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC13"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC13"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC8"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC14"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H4> 3.1.2.4 ANSI-C Quoting </H4> +<!--docid::SEC12::--> +<P> + +Words of the form <CODE>$'<VAR>string</VAR>'</CODE> are treated specially. The +word expands to <VAR>string</VAR>, with backslash-escaped characters replaced +as specified by the ANSI C standard. Backslash escape sequences, if +present, are decoded as follows: +</P><P> + +<DL COMPACT> +<DT><CODE>\a</CODE> +<DD>alert (bell) +<DT><CODE>\b</CODE> +<DD>backspace +<DT><CODE>\e</CODE> +<DD><DT><CODE>\E</CODE> +<DD>an escape character (not ANSI C) +<DT><CODE>\f</CODE> +<DD>form feed +<DT><CODE>\n</CODE> +<DD>newline +<DT><CODE>\r</CODE> +<DD>carriage return +<DT><CODE>\t</CODE> +<DD>horizontal tab +<DT><CODE>\v</CODE> +<DD>vertical tab +<DT><CODE>\\</CODE> +<DD>backslash +<DT><CODE>\'</CODE> +<DD>single quote +<DT><CODE>\"</CODE> +<DD>double quote +<DT><CODE>\<VAR>nnn</VAR></CODE> +<DD>the eight-bit character whose value is the octal value <VAR>nnn</VAR> +(one to three digits) +<DT><CODE>\x<VAR>HH</VAR></CODE> +<DD>the eight-bit character whose value is the hexadecimal value <VAR>HH</VAR> +(one or two hex digits) +<DT><CODE>\c<VAR>x</VAR></CODE> +<DD>a control-<VAR>x</VAR> character +</DL> +<P> + +The expanded result is single-quoted, as if the dollar sign had not +been present. +</P><P> + +<A NAME="Locale Translation"></A> +<HR SIZE="6"> +<A NAME="SEC13"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC12"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC14"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC14"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC8"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC14"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H4> 3.1.2.5 Locale-Specific Translation </H4> +<!--docid::SEC13::--> +<P> + +A double-quoted string preceded by a dollar sign (<SAMP>`$'</SAMP>) will cause +the string to be translated according to the current locale. +If the current locale is <CODE>C</CODE> or <CODE>POSIX</CODE>, the dollar sign +is ignored. +If the string is translated and replaced, the replacement is +double-quoted. +</P><P> + +<A NAME="IDX21"></A> +<A NAME="IDX22"></A> +<A NAME="IDX23"></A> +Some systems use the message catalog selected by the <CODE>LC_MESSAGES</CODE> +shell variable. Others create the name of the message catalog from the +value of the <CODE>TEXTDOMAIN</CODE> shell variable, possibly adding a +suffix of <SAMP>`.mo'</SAMP>. If you use the <CODE>TEXTDOMAIN</CODE> variable, you +may need to set the <CODE>TEXTDOMAINDIR</CODE> variable to the location of +the message catalog files. Still others use both variables in this +fashion: +<CODE>TEXTDOMAINDIR</CODE>/<CODE>LC_MESSAGES</CODE>/LC_MESSAGES/<CODE>TEXTDOMAIN</CODE>.mo. +</P><P> + +<A NAME="Comments"></A> +<HR SIZE="6"> +<A NAME="SEC14"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC13"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC15"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC5"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC6"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC15"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 3.1.3 Comments </H3> +<!--docid::SEC14::--> +<P> + +In a non-interactive shell, or an interactive shell in which the +<CODE>interactive_comments</CODE> option to the <CODE>shopt</CODE> +builtin is enabled (see section <A HREF="bashref.html#SEC63">4.3.2 The Shopt Builtin</A>), +a word beginning with <SAMP>`#'</SAMP> +causes that word and all remaining characters on that line to +be ignored. An interactive shell without the <CODE>interactive_comments</CODE> +option enabled does not allow comments. The <CODE>interactive_comments</CODE> +option is on by default in interactive shells. +See section <A HREF="bashref.html#SEC78">6.3 Interactive Shells</A>, for a description of what makes +a shell interactive. +</P><P> + +<A NAME="Shell Commands"></A> +<HR SIZE="6"> +<A NAME="SEC15"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC14"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC16"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC24"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC5"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC24"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H2> 3.2 Shell Commands </H2> +<!--docid::SEC15::--> +<P> + +A simple shell command such as <CODE>echo a b c</CODE> consists of the command +itself followed by arguments, separated by spaces. +</P><P> + +More complex shell commands are composed of simple commands arranged together +in a variety of ways: in a pipeline in which the output of one command +becomes the input of a second, in a loop or conditional construct, or in +some other grouping. +</P><P> + +<BLOCKQUOTE><TABLE BORDER=0 CELLSPACING=0> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC16">3.2.1 Simple Commands</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">The most common type of command.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC17">3.2.2 Pipelines</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Connecting the input and output of several + commands.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC18">3.2.3 Lists of Commands</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">How to execute commands sequentially.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC19">3.2.4 Compound Commands</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Shell commands for control flow.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC23">3.2.5 Coprocesses</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Two-way communication between commands.</TD></TR> +</TABLE></BLOCKQUOTE> +<P> + +<A NAME="Simple Commands"></A> +<HR SIZE="6"> +<A NAME="SEC16"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC15"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC17"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC24"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC15"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC24"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 3.2.1 Simple Commands </H3> +<!--docid::SEC16::--> +<P> + +A simple command is the kind of command encountered most often. +It's just a sequence of words separated by <CODE>blank</CODE>s, terminated +by one of the shell's control operators (see section <A HREF="bashref.html#SEC4">2. Definitions</A>). The +first word generally specifies a command to be executed, with the +rest of the words being that command's arguments. +</P><P> + +The return status (see section <A HREF="bashref.html#SEC55">3.7.5 Exit Status</A>) of a simple command is +its exit status as provided +by the POSIX 1003.1 <CODE>waitpid</CODE> function, or 128+<VAR>n</VAR> if +the command was terminated by signal <VAR>n</VAR>. +</P><P> + +<A NAME="Pipelines"></A> +<HR SIZE="6"> +<A NAME="SEC17"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC16"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC18"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC18"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC15"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC24"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 3.2.2 Pipelines </H3> +<!--docid::SEC17::--> +<P> + +A <CODE>pipeline</CODE> is a sequence of simple commands separated by one of +the control operators <SAMP>`|'</SAMP> or <SAMP>`|&'</SAMP>. +</P><P> + +<A NAME="IDX24"></A> +<A NAME="IDX25"></A> +<A NAME="IDX26"></A> +The format for a pipeline is +<TABLE><tr><td> </td><td class=example><pre>[<CODE>time</CODE> [<CODE>-p</CODE>]] [<CODE>!</CODE>] <VAR>command1</VAR> [ [<CODE>|</CODE> or <CODE>|&</CODE>] <VAR>command2</VAR> <small>...</small>] +</pre></td></tr></table></P><P> + +The output of each command in the pipeline is connected via a pipe +to the input of the next command. +That is, each command reads the previous command's output. This +connection is performed before any redirections specified by the +command. +</P><P> + +If <SAMP>`|&'</SAMP> is used, the standard error of <VAR>command1</VAR> is connected to +<VAR>command2</VAR>'s standard input through the pipe; it is shorthand for +<CODE>2>&1 |</CODE>. This implicit redirection of the standard error is +performed after any redirections specified by the command. +</P><P> + +The reserved word <CODE>time</CODE> causes timing statistics +to be printed for the pipeline once it finishes. +The statistics currently consist of elapsed (wall-clock) time and +user and system time consumed by the command's execution. +The <SAMP>`-p'</SAMP> option changes the output format to that specified +by POSIX. +The <CODE>TIMEFORMAT</CODE> variable may be set to a format string that +specifies how the timing information should be displayed. +See section <A HREF="bashref.html#SEC67">5.2 Bash Variables</A>, for a description of the available formats. +The use of <CODE>time</CODE> as a reserved word permits the timing of +shell builtins, shell functions, and pipelines. An external +<CODE>time</CODE> command cannot time these easily. +</P><P> + +If the pipeline is not executed asynchronously (see section <A HREF="bashref.html#SEC18">3.2.3 Lists of Commands</A>), the +shell waits for all commands in the pipeline to complete. +</P><P> + +Each command in a pipeline is executed in its own subshell +(see section <A HREF="bashref.html#SEC53">3.7.3 Command Execution Environment</A>). The exit +status of a pipeline is the exit status of the last command in the +pipeline, unless the <CODE>pipefail</CODE> option is enabled +(see section <A HREF="bashref.html#SEC62">4.3.1 The Set Builtin</A>). +If <CODE>pipefail</CODE> is enabled, the pipeline's return status is the +value of the last (rightmost) command to exit with a non-zero status, +or zero if all commands exit successfully. +If the reserved word <SAMP>`!'</SAMP> precedes the pipeline, the +exit status is the logical negation of the exit status as described +above. +The shell waits for all commands in the pipeline to terminate before +returning a value. +</P><P> + +<A NAME="Lists"></A> +<HR SIZE="6"> +<A NAME="SEC18"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC17"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC19"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC19"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC15"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC24"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 3.2.3 Lists of Commands </H3> +<!--docid::SEC18::--> +<P> + +A <CODE>list</CODE> is a sequence of one or more pipelines separated by one +of the operators <SAMP>`;'</SAMP>, <SAMP>`&'</SAMP>, <SAMP>`&&'</SAMP>, or <SAMP>`||'</SAMP>, +and optionally terminated by one of <SAMP>`;'</SAMP>, <SAMP>`&'</SAMP>, or a +<CODE>newline</CODE>. +</P><P> + +Of these list operators, <SAMP>`&&'</SAMP> and <SAMP>`||'</SAMP> +have equal precedence, followed by <SAMP>`;'</SAMP> and <SAMP>`&'</SAMP>, +which have equal precedence. +</P><P> + +A sequence of one or more newlines may appear in a <CODE>list</CODE> +to delimit commands, equivalent to a semicolon. +</P><P> + +If a command is terminated by the control operator <SAMP>`&'</SAMP>, +the shell executes the command asynchronously in a subshell. +This is known as executing the command in the <VAR>background</VAR>. +The shell does not wait for the command to finish, and the return +status is 0 (true). +When job control is not active (see section <A HREF="bashref.html#SEC91">7. Job Control</A>), +the standard input for asynchronous commands, in the absence of any +explicit redirections, is redirected from <CODE>/dev/null</CODE>. +</P><P> + +Commands separated by a <SAMP>`;'</SAMP> are executed sequentially; the shell +waits for each command to terminate in turn. The return status is the +exit status of the last command executed. +</P><P> + +AND and OR lists are sequences of one or more pipelines +separated by the control operators <SAMP>`&&'</SAMP> and <SAMP>`||'</SAMP>, +respectively. AND and OR lists are executed with left +associativity. +</P><P> + +An AND list has the form +<TABLE><tr><td> </td><td class=example><pre><VAR>command1</VAR> && <VAR>command2</VAR> +</pre></td></tr></table></P><P> + +<VAR>command2</VAR> is executed if, and only if, <VAR>command1</VAR> +returns an exit status of zero. +</P><P> + +An OR list has the form +<TABLE><tr><td> </td><td class=example><pre><VAR>command1</VAR> || <VAR>command2</VAR> +</pre></td></tr></table></P><P> + +<VAR>command2</VAR> is executed if, and only if, <VAR>command1</VAR> +returns a non-zero exit status. +</P><P> + +The return status of +AND and OR lists is the exit status of the last command +executed in the list. +</P><P> + +<A NAME="Compound Commands"></A> +<HR SIZE="6"> +<A NAME="SEC19"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC18"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC20"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC23"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC15"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC23"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 3.2.4 Compound Commands </H3> +<!--docid::SEC19::--> +<P> + +<BLOCKQUOTE><TABLE BORDER=0 CELLSPACING=0> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC20">3.2.4.1 Looping Constructs</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Shell commands for iterative action.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC21">3.2.4.2 Conditional Constructs</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Shell commands for conditional execution.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC22">3.2.4.3 Grouping Commands</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Ways to group commands.</TD></TR> +</TABLE></BLOCKQUOTE> +<P> + +Compound commands are the shell programming constructs. +Each construct begins with a reserved word or control operator and is +terminated by a corresponding reserved word or operator. +Any redirections (see section <A HREF="bashref.html#SEC39">3.6 Redirections</A>) associated with a compound command +apply to all commands within that compound command unless explicitly overridden. +</P><P> + +Bash provides looping constructs, conditional commands, and mechanisms +to group commands and execute them as a unit. +</P><P> + +<A NAME="Looping Constructs"></A> +<HR SIZE="6"> +<A NAME="SEC20"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC19"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC21"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC23"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC19"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC23"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H4> 3.2.4.1 Looping Constructs </H4> +<!--docid::SEC20::--> +<P> + +Bash supports the following looping constructs. +</P><P> + +Note that wherever a <SAMP>`;'</SAMP> appears in the description of a +command's syntax, it may be replaced with one or more newlines. +</P><P> + +<DL COMPACT> +<DT><CODE>until</CODE> +<DD><A NAME="IDX27"></A> +<A NAME="IDX28"></A> +<A NAME="IDX29"></A> +The syntax of the <CODE>until</CODE> command is: +<TABLE><tr><td> </td><td class=example><pre>until <VAR>test-commands</VAR>; do <VAR>consequent-commands</VAR>; done +</pre></td></tr></table>Execute <VAR>consequent-commands</VAR> as long as +<VAR>test-commands</VAR> has an exit status which is not zero. +The return status is the exit status of the last command executed +in <VAR>consequent-commands</VAR>, or zero if none was executed. +<P> + +<DT><CODE>while</CODE> +<DD><A NAME="IDX30"></A> +The syntax of the <CODE>while</CODE> command is: +<TABLE><tr><td> </td><td class=example><pre>while <VAR>test-commands</VAR>; do <VAR>consequent-commands</VAR>; done +</pre></td></tr></table><P> + +Execute <VAR>consequent-commands</VAR> as long as +<VAR>test-commands</VAR> has an exit status of zero. +The return status is the exit status of the last command executed +in <VAR>consequent-commands</VAR>, or zero if none was executed. +</P><P> + +<DT><CODE>for</CODE> +<DD><A NAME="IDX31"></A> +The syntax of the <CODE>for</CODE> command is: +<P> + +<TABLE><tr><td> </td><td class=example><pre>for <VAR>name</VAR> [ [in [<VAR>words</VAR> <small>...</small>] ] ; ] do <VAR>commands</VAR>; done +</pre></td></tr></table>Expand <VAR>words</VAR>, and execute <VAR>commands</VAR> once for each member +in the resultant list, with <VAR>name</VAR> bound to the current member. +If <SAMP>`in <VAR>words</VAR>'</SAMP> is not present, the <CODE>for</CODE> command +executes the <VAR>commands</VAR> once for each positional parameter that is +set, as if <SAMP>`in "$@"'</SAMP> had been specified +(see section <A HREF="bashref.html#SEC27">3.4.2 Special Parameters</A>). +The return status is the exit status of the last command that executes. +If there are no items in the expansion of <VAR>words</VAR>, no commands are +executed, and the return status is zero. +</P><P> + +An alternate form of the <CODE>for</CODE> command is also supported: +</P><P> + +<TABLE><tr><td> </td><td class=example><pre>for (( <VAR>expr1</VAR> ; <VAR>expr2</VAR> ; <VAR>expr3</VAR> )) ; do <VAR>commands</VAR> ; done +</pre></td></tr></table>First, the arithmetic expression <VAR>expr1</VAR> is evaluated according +to the rules described below (see section <A HREF="bashref.html#SEC83">6.5 Shell Arithmetic</A>). +The arithmetic expression <VAR>expr2</VAR> is then evaluated repeatedly +until it evaluates to zero. +Each time <VAR>expr2</VAR> evaluates to a non-zero value, <VAR>commands</VAR> are +executed and the arithmetic expression <VAR>expr3</VAR> is evaluated. +If any expression is omitted, it behaves as if it evaluates to 1. +The return value is the exit status of the last command in <VAR>list</VAR> +that is executed, or false if any of the expressions is invalid. +</P><P> + +</DL> +<P> + +The <CODE>break</CODE> and <CODE>continue</CODE> builtins (see section <A HREF="bashref.html#SEC59">4.1 Bourne Shell Builtins</A>) +may be used to control loop execution. +</P><P> + +<A NAME="Conditional Constructs"></A> +<HR SIZE="6"> +<A NAME="SEC21"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC20"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC22"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC22"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC19"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC23"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H4> 3.2.4.2 Conditional Constructs </H4> +<!--docid::SEC21::--> +<P> + +<DL COMPACT> +<DT><CODE>if</CODE> +<DD><A NAME="IDX32"></A> +<A NAME="IDX33"></A> +<A NAME="IDX34"></A> +<A NAME="IDX35"></A> +<A NAME="IDX36"></A> +The syntax of the <CODE>if</CODE> command is: +<P> + +<TABLE><tr><td> </td><td class=example><pre>if <VAR>test-commands</VAR>; then + <VAR>consequent-commands</VAR>; +[elif <VAR>more-test-commands</VAR>; then + <VAR>more-consequents</VAR>;] +[else <VAR>alternate-consequents</VAR>;] +fi +</pre></td></tr></table></P><P> + +The <VAR>test-commands</VAR> list is executed, and if its return status is zero, +the <VAR>consequent-commands</VAR> list is executed. +If <VAR>test-commands</VAR> returns a non-zero status, each <CODE>elif</CODE> list +is executed in turn, and if its exit status is zero, +the corresponding <VAR>more-consequents</VAR> is executed and the +command completes. +If <SAMP>`else <VAR>alternate-consequents</VAR>'</SAMP> is present, and +the final command in the final <CODE>if</CODE> or <CODE>elif</CODE> clause +has a non-zero exit status, then <VAR>alternate-consequents</VAR> is executed. +The return status is the exit status of the last command executed, or +zero if no condition tested true. +</P><P> + +<DT><CODE>case</CODE> +<DD><A NAME="IDX37"></A> +<A NAME="IDX38"></A> +<A NAME="IDX39"></A> +The syntax of the <CODE>case</CODE> command is: +<P> + +<TABLE><tr><td> </td><td class=example><pre><CODE>case <VAR>word</VAR> in [ [(] <VAR>pattern</VAR> [| <VAR>pattern</VAR>]<small>...</small>) <VAR>command-list</VAR> ;;]<small>...</small> esac</CODE> +</pre></td></tr></table></P><P> + +<CODE>case</CODE> will selectively execute the <VAR>command-list</VAR> corresponding to +the first <VAR>pattern</VAR> that matches <VAR>word</VAR>. +If the shell option <CODE>nocasematch</CODE> +(see the description of <CODE>shopt</CODE> in <A HREF="bashref.html#SEC63">4.3.2 The Shopt Builtin</A>) +is enabled, the match is performed without regard to the case +of alphabetic characters. +The <SAMP>`|'</SAMP> is used to separate multiple patterns, and the <SAMP>`)'</SAMP> +operator terminates a pattern list. +A list of patterns and an associated command-list is known +as a <VAR>clause</VAR>. +</P><P> + +Each clause must be terminated with <SAMP>`;;'</SAMP>, <SAMP>`;&'</SAMP>, or <SAMP>`;;&'</SAMP>. +The <VAR>word</VAR> undergoes tilde expansion, parameter expansion, command +substitution, arithmetic expansion, and quote removal before matching is +attempted. Each <VAR>pattern</VAR> undergoes tilde expansion, parameter +expansion, command substitution, and arithmetic expansion. +</P><P> + +There may be an arbitrary number of <CODE>case</CODE> clauses, each terminated +by a <SAMP>`;;'</SAMP>, <SAMP>`;&'</SAMP>, or <SAMP>`;;&'</SAMP>. +The first pattern that matches determines the +command-list that is executed. +</P><P> + +Here is an example using <CODE>case</CODE> in a script that could be used to +describe one interesting feature of an animal: +</P><P> + +<TABLE><tr><td> </td><td class=example><pre>echo -n "Enter the name of an animal: " +read ANIMAL +echo -n "The $ANIMAL has " +case $ANIMAL in + horse | dog | cat) echo -n "four";; + man | kangaroo ) echo -n "two";; + *) echo -n "an unknown number of";; +esac +echo " legs." +</pre></td></tr></table></P><P> + +</P><P> + +If the <SAMP>`;;'</SAMP> operator is used, no subsequent matches are attempted after +the first pattern match. +Using <SAMP>`;&'</SAMP> in place of <SAMP>`;;'</SAMP> causes execution to continue with +the <VAR>command-list</VAR> associated with the next clause, if any. +Using <SAMP>`;;&'</SAMP> in place of <SAMP>`;;'</SAMP> causes the shell to test the patterns +in the next clause, if any, and execute any associated <VAR>command-list</VAR> +on a successful match. +</P><P> + +The return status is zero if no <VAR>pattern</VAR> is matched. Otherwise, the +return status is the exit status of the <VAR>command-list</VAR> executed. +</P><P> + +<DT><CODE>select</CODE> +<DD><A NAME="IDX40"></A> +<P> + +The <CODE>select</CODE> construct allows the easy generation of menus. +It has almost the same syntax as the <CODE>for</CODE> command: +</P><P> + +<TABLE><tr><td> </td><td class=example><pre>select <VAR>name</VAR> [in <VAR>words</VAR> <small>...</small>]; do <VAR>commands</VAR>; done +</pre></td></tr></table></P><P> + +The list of words following <CODE>in</CODE> is expanded, generating a list +of items. The set of expanded words is printed on the standard +error output stream, each preceded by a number. If the +<SAMP>`in <VAR>words</VAR>'</SAMP> is omitted, the positional parameters are printed, +as if <SAMP>`in "$@"'</SAMP> had been specified. +The <CODE>PS3</CODE> prompt is then displayed and a line is read from the +standard input. +If the line consists of a number corresponding to one of the displayed +words, then the value of <VAR>name</VAR> is set to that word. +If the line is empty, the words and prompt are displayed again. +If <CODE>EOF</CODE> is read, the <CODE>select</CODE> command completes. +Any other value read causes <VAR>name</VAR> to be set to null. +The line read is saved in the variable <CODE>REPLY</CODE>. +</P><P> + +The <VAR>commands</VAR> are executed after each selection until a +<CODE>break</CODE> command is executed, at which +point the <CODE>select</CODE> command completes. +</P><P> + +Here is an example that allows the user to pick a filename from the +current directory, and displays the name and index of the file +selected. +</P><P> + +<TABLE><tr><td> </td><td class=example><pre>select fname in *; +do + echo you picked $fname \($REPLY\) + break; +done +</pre></td></tr></table></P><P> + +<DT><CODE>((<small>...</small>))</CODE> +<DD><TABLE><tr><td> </td><td class=example><pre>(( <VAR>expression</VAR> )) +</pre></td></tr></table><P> + +The arithmetic <VAR>expression</VAR> is evaluated according to the rules +described below (see section <A HREF="bashref.html#SEC83">6.5 Shell Arithmetic</A>). +If the value of the expression is non-zero, the return status is 0; +otherwise the return status is 1. This is exactly equivalent to +<TABLE><tr><td> </td><td class=example><pre>let "<VAR>expression</VAR>" +</pre></td></tr></table>See section <A HREF="bashref.html#SEC60">4.2 Bash Builtin Commands</A>, for a full description of the <CODE>let</CODE> builtin. +</P><P> + +<DT><CODE>[[<small>...</small>]]</CODE> +<DD><A NAME="IDX41"></A> +<A NAME="IDX42"></A> +<TABLE><tr><td> </td><td class=example><pre>[[ <VAR>expression</VAR> ]] +</pre></td></tr></table><P> + +Return a status of 0 or 1 depending on the evaluation of +the conditional expression <VAR>expression</VAR>. +Expressions are composed of the primaries described below in +<A HREF="bashref.html#SEC82">6.4 Bash Conditional Expressions</A>. +Word splitting and filename expansion are not performed on the words +between the <SAMP>`[['</SAMP> and <SAMP>`]]'</SAMP>; tilde expansion, parameter and +variable expansion, arithmetic expansion, command substitution, process +substitution, and quote removal are performed. +Conditional operators such as <SAMP>`-f'</SAMP> must be unquoted to be recognized +as primaries. +</P><P> + +When used with <SAMP>`[['</SAMP>, The <SAMP>`<'</SAMP> and <SAMP>`>'</SAMP> operators sort +lexicographically using the current locale. +</P><P> + +When the <SAMP>`=='</SAMP> and <SAMP>`!='</SAMP> operators are used, the string to the +right of the operator is considered a pattern and matched according +to the rules described below in <A HREF="bashref.html#SEC37">3.5.8.1 Pattern Matching</A>. +If the shell option <CODE>nocasematch</CODE> +(see the description of <CODE>shopt</CODE> in <A HREF="bashref.html#SEC63">4.3.2 The Shopt Builtin</A>) +is enabled, the match is performed without regard to the case +of alphabetic characters. +The return value is 0 if the string matches (<SAMP>`=='</SAMP>) or does not +match (<SAMP>`!='</SAMP>)the pattern, and 1 otherwise. +Any part of the pattern may be quoted to force it to be matched as a +string. +</P><P> + +An additional binary operator, <SAMP>`=~'</SAMP>, is available, with the same +precedence as <SAMP>`=='</SAMP> and <SAMP>`!='</SAMP>. +When it is used, the string to the right of the operator is considered +an extended regular expression and matched accordingly (as in <I>regex</I>3)). +The return value is 0 if the string matches +the pattern, and 1 otherwise. +If the regular expression is syntactically incorrect, the conditional +expression's return value is 2. +If the shell option <CODE>nocasematch</CODE> +(see the description of <CODE>shopt</CODE> in <A HREF="bashref.html#SEC63">4.3.2 The Shopt Builtin</A>) +is enabled, the match is performed without regard to the case +of alphabetic characters. +Any part of the pattern may be quoted to force it to be matched as a +string. +Substrings matched by parenthesized subexpressions within the regular +expression are saved in the array variable <CODE>BASH_REMATCH</CODE>. +The element of <CODE>BASH_REMATCH</CODE> with index 0 is the portion of the string +matching the entire regular expression. +The element of <CODE>BASH_REMATCH</CODE> with index <VAR>n</VAR> is the portion of the +string matching the <VAR>n</VAR>th parenthesized subexpression. +</P><P> + +Expressions may be combined using the following operators, listed +in decreasing order of precedence: +</P><P> + +<DL COMPACT> +<DT><CODE>( <VAR>expression</VAR> )</CODE> +<DD>Returns the value of <VAR>expression</VAR>. +This may be used to override the normal precedence of operators. +<P> + +<DT><CODE>! <VAR>expression</VAR></CODE> +<DD>True if <VAR>expression</VAR> is false. +<P> + +<DT><CODE><VAR>expression1</VAR> && <VAR>expression2</VAR></CODE> +<DD>True if both <VAR>expression1</VAR> and <VAR>expression2</VAR> are true. +<P> + +<DT><CODE><VAR>expression1</VAR> || <VAR>expression2</VAR></CODE> +<DD>True if either <VAR>expression1</VAR> or <VAR>expression2</VAR> is true. +</DL> +The <CODE>&&</CODE> and <CODE>||</CODE> operators do not evaluate <VAR>expression2</VAR> if the +value of <VAR>expression1</VAR> is sufficient to determine the return +value of the entire conditional expression. +<P> + +</DL> +<P> + +<A NAME="Command Grouping"></A> +<HR SIZE="6"> +<A NAME="SEC22"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC21"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC23"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC23"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC19"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC23"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H4> 3.2.4.3 Grouping Commands </H4> +<!--docid::SEC22::--> +<P> + +Bash provides two ways to group a list of commands to be executed +as a unit. When commands are grouped, redirections may be applied +to the entire command list. For example, the output of all the +commands in the list may be redirected to a single stream. +</P><P> + +<DL COMPACT> +<DT><CODE>()</CODE> +<DD><TABLE><tr><td> </td><td class=example><pre>( <VAR>list</VAR> ) +</pre></td></tr></table><P> + +Placing a list of commands between parentheses causes a subshell +environment to be created (see section <A HREF="bashref.html#SEC53">3.7.3 Command Execution Environment</A>), and each +of the commands in <VAR>list</VAR> to be executed in that subshell. Since the +<VAR>list</VAR> is executed in a subshell, variable assignments do not remain in +effect after the subshell completes. +</P><P> + +<DT><CODE>{}</CODE> +<DD><A NAME="IDX43"></A> +<A NAME="IDX44"></A> +<TABLE><tr><td> </td><td class=example><pre>{ <VAR>list</VAR>; } +</pre></td></tr></table><P> + +Placing a list of commands between curly braces causes the list to +be executed in the current shell context. No subshell is created. +The semicolon (or newline) following <VAR>list</VAR> is required. +</DL> +<P> + +In addition to the creation of a subshell, there is a subtle difference +between these two constructs due to historical reasons. The braces +are <CODE>reserved words</CODE>, so they must be separated from the <VAR>list</VAR> +by <CODE>blank</CODE>s or other shell metacharacters. +The parentheses are <CODE>operators</CODE>, and are +recognized as separate tokens by the shell even if they are not separated +from the <VAR>list</VAR> by whitespace. +</P><P> + +The exit status of both of these constructs is the exit status of +<VAR>list</VAR>. +</P><P> + +<A NAME="Coprocesses"></A> +<HR SIZE="6"> +<A NAME="SEC23"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC22"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC24"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC24"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC15"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC24"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 3.2.5 Coprocesses </H3> +<!--docid::SEC23::--> +<P> + +A <CODE>coprocess</CODE> is a shell command preceded by the <CODE>coproc</CODE> +reserved word. +A coprocess is executed asynchronously in a subshell, as if the command +had been terminated with the <SAMP>`&'</SAMP> control operator, with a two-way pipe +established between the executing shell and the coprocess. +</P><P> + +The format for a coprocess is: +<TABLE><tr><td> </td><td class=example><pre><CODE>coproc</CODE> [<VAR>NAME</VAR>] <VAR>command</VAR> [<VAR>redirections</VAR>] +</pre></td></tr></table></P><P> + +This creates a coprocess named <VAR>NAME</VAR>. +If <VAR>NAME</VAR> is not supplied, the default name is <VAR>COPROC</VAR>. +<VAR>NAME</VAR> must not be supplied if <VAR>command</VAR> is a simple +command (see section <A HREF="bashref.html#SEC16">3.2.1 Simple Commands</A>); otherwise, it is interpreted as +the first word of the simple command. +</P><P> + +When the coproc is executed, the shell creates an array variable +(see section <A HREF="bashref.html#SEC85">6.7 Arrays</A>) +named <VAR>NAME</VAR> in the context of the executing shell. +The standard output of <VAR>command</VAR> +is connected via a pipe to a file descriptor in the executing shell, +and that file descriptor is assigned to <VAR>NAME</VAR>[0]. +The standard input of <VAR>command</VAR> +is connected via a pipe to a file descriptor in the executing shell, +and that file descriptor is assigned to <VAR>NAME</VAR>[1]. +This pipe is established before any redirections specified by the +command (see section <A HREF="bashref.html#SEC39">3.6 Redirections</A>). +The file descriptors can be utilized as arguments to shell commands +and redirections using standard word expansions. +</P><P> + +The process id of the shell spawned to execute the coprocess is +available as the value of the variable <VAR>NAME</VAR>_PID. +The <CODE>wait</CODE> +builtin command may be used to wait for the coprocess to terminate. +</P><P> + +The return status of a coprocess is the exit status of <VAR>command</VAR>. +</P><P> + +<A NAME="Shell Functions"></A> +<HR SIZE="6"> +<A NAME="SEC24"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC23"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC25"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC25"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC5"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC58"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H2> 3.3 Shell Functions </H2> +<!--docid::SEC24::--> +<P> + +Shell functions are a way to group commands for later execution +using a single name for the group. They are executed just like +a "regular" command. +When the name of a shell function is used as a simple command name, +the list of commands associated with that function name is executed. +Shell functions are executed in the current +shell context; no new process is created to interpret them. +</P><P> + +Functions are declared using this syntax: +<A NAME="IDX45"></A> +<TABLE><tr><td> </td><td class=example><pre>[ <CODE>function</CODE> ] <VAR>name</VAR> () <VAR>compound-command</VAR> [ <VAR>redirections</VAR> ] +</pre></td></tr></table></P><P> + +This defines a shell function named <VAR>name</VAR>. The reserved +word <CODE>function</CODE> is optional. +If the <CODE>function</CODE> reserved +word is supplied, the parentheses are optional. +The <VAR>body</VAR> of the function is the compound command +<VAR>compound-command</VAR> (see section <A HREF="bashref.html#SEC19">3.2.4 Compound Commands</A>). +That command is usually a <VAR>list</VAR> enclosed between { and }, but +may be any compound command listed above. +<VAR>compound-command</VAR> is executed whenever <VAR>name</VAR> is specified as the +name of a command. +Any redirections (see section <A HREF="bashref.html#SEC39">3.6 Redirections</A>) associated with the shell function +are performed when the function is executed. +</P><P> + +A function definition may be deleted using the <SAMP>`-f'</SAMP> option to the +<CODE>unset</CODE> builtin (see section <A HREF="bashref.html#SEC59">4.1 Bourne Shell Builtins</A>). +</P><P> + +The exit status of a function definition is zero unless a syntax error +occurs or a readonly function with the same name already exists. +When executed, the exit status of a function is the exit status of the +last command executed in the body. +</P><P> + +Note that for historical reasons, in the most common usage the curly braces +that surround the body of the function must be separated from the body by +<CODE>blank</CODE>s or newlines. +This is because the braces are reserved words and are only recognized +as such when they are separated from the command list +by whitespace or another shell metacharacter. +Also, when using the braces, the <VAR>list</VAR> must be terminated by a semicolon, +a <SAMP>`&'</SAMP>, or a newline. +</P><P> + +When a function is executed, the arguments to the +function become the positional parameters +during its execution (see section <A HREF="bashref.html#SEC26">3.4.1 Positional Parameters</A>). +The special parameter <SAMP>`#'</SAMP> that expands to the number of +positional parameters is updated to reflect the change. +Special parameter <CODE>0</CODE> is unchanged. +The first element of the <CODE>FUNCNAME</CODE> variable is set to the +name of the function while the function is executing. +</P><P> + +All other aspects of the shell execution +environment are identical between a function and its caller +with these exceptions: +the <CODE>DEBUG</CODE> and <CODE>RETURN</CODE> traps +are not inherited unless the function has been given the +<CODE>trace</CODE> attribute using the <CODE>declare</CODE> builtin or +the <CODE>-o functrace</CODE> option has been enabled with +the <CODE>set</CODE> builtin, +(in which case all functions inherit the <CODE>DEBUG</CODE> and <CODE>RETURN</CODE> traps), +and the <CODE>ERR</CODE> trap is not inherited unless the <CODE>-o errtrace</CODE> +shell option has been enabled. +See section <A HREF="bashref.html#SEC59">4.1 Bourne Shell Builtins</A>, for the description of the +<CODE>trap</CODE> builtin. +</P><P> + +If the builtin command <CODE>return</CODE> +is executed in a function, the function completes and +execution resumes with the next command after the function +call. +Any command associated with the <CODE>RETURN</CODE> trap is executed +before execution resumes. +When a function completes, the values of the +positional parameters and the special parameter <SAMP>`#'</SAMP> +are restored to the values they had prior to the function's +execution. If a numeric argument is given to <CODE>return</CODE>, +that is the function's return status; otherwise the function's +return status is the exit status of the last command executed +before the <CODE>return</CODE>. +</P><P> + +Variables local to the function may be declared with the +<CODE>local</CODE> builtin. These variables are visible only to +the function and the commands it invokes. +</P><P> + +Function names and definitions may be listed with the +<SAMP>`-f'</SAMP> option to the <CODE>declare</CODE> or <CODE>typeset</CODE> +builtin commands (see section <A HREF="bashref.html#SEC60">4.2 Bash Builtin Commands</A>). +The <SAMP>`-F'</SAMP> option to <CODE>declare</CODE> or <CODE>typeset</CODE> +will list the function names only +(and optionally the source file and line number, if the <CODE>extdebug</CODE> +shell option is enabled). +Functions may be exported so that subshells +automatically have them defined with the +<SAMP>`-f'</SAMP> option to the <CODE>export</CODE> builtin +(see section <A HREF="bashref.html#SEC59">4.1 Bourne Shell Builtins</A>). +Note that shell functions and variables with the same name may result +in multiple identically-named entries in the environment passed to the +shell's children. +Care should be taken in cases where this may cause a problem. +</P><P> + +Functions may be recursive. No limit is placed on the number of +recursive calls. +</P><P> + +<A NAME="Shell Parameters"></A> +<HR SIZE="6"> +<A NAME="SEC25"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC24"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC26"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC28"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC5"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC28"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H2> 3.4 Shell Parameters </H2> +<!--docid::SEC25::--> +<P> + +<BLOCKQUOTE><TABLE BORDER=0 CELLSPACING=0> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC26">3.4.1 Positional Parameters</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">The shell's command-line arguments.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC27">3.4.2 Special Parameters</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Parameters denoted by special characters.</TD></TR> +</TABLE></BLOCKQUOTE> +<P> + +A <VAR>parameter</VAR> is an entity that stores values. +It can be a <CODE>name</CODE>, a number, or one of the special characters +listed below. +A <VAR>variable</VAR> is a parameter denoted by a <CODE>name</CODE>. +A variable has a <VAR>value</VAR> and zero or more <VAR>attributes</VAR>. +Attributes are assigned using the <CODE>declare</CODE> builtin command +(see the description of the <CODE>declare</CODE> builtin in <A HREF="bashref.html#SEC60">4.2 Bash Builtin Commands</A>). +</P><P> + +A parameter is set if it has been assigned a value. The null string is +a valid value. Once a variable is set, it may be unset only by using +the <CODE>unset</CODE> builtin command. +</P><P> + +A variable may be assigned to by a statement of the form +<TABLE><tr><td> </td><td class=example><pre><VAR>name</VAR>=[<VAR>value</VAR>] +</pre></td></tr></table>If <VAR>value</VAR> +is not given, the variable is assigned the null string. All +<VAR>value</VAR>s undergo tilde expansion, parameter and variable expansion, +command substitution, arithmetic expansion, and quote +removal (detailed below). If the variable has its <CODE>integer</CODE> +attribute set, then <VAR>value</VAR> +is evaluated as an arithmetic expression even if the <CODE>$((<small>...</small>))</CODE> +expansion is not used (see section <A HREF="bashref.html#SEC33">3.5.5 Arithmetic Expansion</A>). +Word splitting is not performed, with the exception +of <CODE>"$@"</CODE> as explained below. +Filename expansion is not performed. +Assignment statements may also appear as arguments to the +<CODE>alias</CODE>, +<CODE>declare</CODE>, <CODE>typeset</CODE>, <CODE>export</CODE>, <CODE>readonly</CODE>, +and <CODE>local</CODE> builtin commands. +</P><P> + +In the context where an assignment statement is assigning a value +to a shell variable or array index (see section <A HREF="bashref.html#SEC85">6.7 Arrays</A>), the <SAMP>`+='</SAMP> +operator can be used to +append to or add to the variable's previous value. +When <SAMP>`+='</SAMP> is applied to a variable for which the integer attribute +has been set, <VAR>value</VAR> is evaluated as an arithmetic expression and +added to the variable's current value, which is also evaluated. +When <SAMP>`+='</SAMP> is applied to an array variable using compound assignment +(see section <A HREF="bashref.html#SEC85">6.7 Arrays</A>), the +variable's value is not unset (as it is when using <SAMP>`='</SAMP>), and new +values are appended to the array beginning at one greater than the array's +maximum index (for indexed arrays), or added as additional key-value pairs +in an associative array. +When applied to a string-valued variable, <VAR>value</VAR> is expanded and +appended to the variable's value. +</P><P> + +<A NAME="Positional Parameters"></A> +<HR SIZE="6"> +<A NAME="SEC26"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC25"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC27"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC28"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC25"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC28"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 3.4.1 Positional Parameters </H3> +<!--docid::SEC26::--> +<P> + +A <VAR>positional parameter</VAR> is a parameter denoted by one or more +digits, other than the single digit <CODE>0</CODE>. Positional parameters are +assigned from the shell's arguments when it is invoked, +and may be reassigned using the <CODE>set</CODE> builtin command. +Positional parameter <CODE>N</CODE> may be referenced as <CODE>${N}</CODE>, or +as <CODE>$N</CODE> when <CODE>N</CODE> consists of a single digit. +Positional parameters may not be assigned to with assignment statements. +The <CODE>set</CODE> and <CODE>shift</CODE> builtins are used to set and +unset them (see section <A HREF="bashref.html#SEC58">4. Shell Builtin Commands</A>). +The positional parameters are +temporarily replaced when a shell function is executed +(see section <A HREF="bashref.html#SEC24">3.3 Shell Functions</A>). +</P><P> + +When a positional parameter consisting of more than a single +digit is expanded, it must be enclosed in braces. +</P><P> + +<A NAME="Special Parameters"></A> +<HR SIZE="6"> +<A NAME="SEC27"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC26"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC28"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC28"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC25"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC28"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 3.4.2 Special Parameters </H3> +<!--docid::SEC27::--> +<P> + +The shell treats several parameters specially. These parameters may +only be referenced; assignment to them is not allowed. +</P><P> + +<DL COMPACT> + +<A NAME="IDX46"></A> +<DT><CODE>*</CODE> +<DD><A NAME="IDX47"></A> +Expands to the positional parameters, starting from one. When the +expansion occurs within double quotes, it expands to a single word +with the value of each parameter separated by the first character +of the <CODE>IFS</CODE> +special variable. That is, <CODE>"$*"</CODE> is equivalent +to <CODE>"$1<VAR>c</VAR>$2<VAR>c</VAR><small>...</small>"</CODE>, where <VAR>c</VAR> +is the first character of the value of the <CODE>IFS</CODE> +variable. +If <CODE>IFS</CODE> is unset, the parameters are separated by spaces. +If <CODE>IFS</CODE> is null, the parameters are joined without intervening +separators. +<P> + +<A NAME="IDX48"></A> +<DT><CODE>@</CODE> +<DD><A NAME="IDX49"></A> +Expands to the positional parameters, starting from one. When the +expansion occurs within double quotes, each parameter expands to a +separate word. That is, <CODE>"$@"</CODE> is equivalent to +<CODE>"$1" "$2" <small>...</small></CODE>. +If the double-quoted expansion occurs within a word, the expansion of +the first parameter is joined with the beginning part of the original +word, and the expansion of the last parameter is joined with the last +part of the original word. +When there are no positional parameters, <CODE>"$@"</CODE> and +<CODE>$@</CODE> +expand to nothing (i.e., they are removed). +<P> + +<A NAME="IDX50"></A> +<DT><CODE>#</CODE> +<DD><A NAME="IDX51"></A> +Expands to the number of positional parameters in decimal. +<P> + +<A NAME="IDX52"></A> +<DT><CODE>?</CODE> +<DD><A NAME="IDX53"></A> +Expands to the exit status of the most recently executed foreground +pipeline. +<P> + +<A NAME="IDX54"></A> +<DT><CODE>-</CODE> +<DD><A NAME="IDX55"></A> +(A hyphen.) Expands to the current option flags as specified upon +invocation, by the <CODE>set</CODE> +builtin command, or those set by the shell itself +(such as the <SAMP>`-i'</SAMP> option). +<P> + +<A NAME="IDX56"></A> +<DT><CODE>$</CODE> +<DD><A NAME="IDX57"></A> +Expands to the process ID of the shell. In a <CODE>()</CODE> subshell, it +expands to the process ID of the invoking shell, not the subshell. +<P> + +<A NAME="IDX58"></A> +<DT><CODE>!</CODE> +<DD><A NAME="IDX59"></A> +Expands to the process ID of the most recently executed background +(asynchronous) command. +<P> + +<A NAME="IDX60"></A> +<DT><CODE>0</CODE> +<DD><A NAME="IDX61"></A> +Expands to the name of the shell or shell script. This is set at +shell initialization. If Bash is invoked with a file of commands +(see section <A HREF="bashref.html#SEC57">3.8 Shell Scripts</A>), <CODE>$0</CODE> is set to the name of that file. +If Bash is started with the <SAMP>`-c'</SAMP> option (see section <A HREF="bashref.html#SEC69">6.1 Invoking Bash</A>), +then <CODE>$0</CODE> is set to the first argument after the string to be +executed, if one is present. Otherwise, it is set +to the filename used to invoke Bash, as given by argument zero. +<P> + +<A NAME="IDX62"></A> +<DT><CODE>_</CODE> +<DD><A NAME="IDX63"></A> +(An underscore.) +At shell startup, set to the absolute pathname used to invoke the +shell or shell script being executed as passed in the environment +or argument list. +Subsequently, expands to the last argument to the previous command, +after expansion. +Also set to the full pathname used to invoke each command executed +and placed in the environment exported to that command. +When checking mail, this parameter holds the name of the mail file. +</DL> +<P> + +<A NAME="Shell Expansions"></A> +<HR SIZE="6"> +<A NAME="SEC28"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC27"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC29"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC39"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC5"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC39"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H2> 3.5 Shell Expansions </H2> +<!--docid::SEC28::--> +<P> + +Expansion is performed on the command line after it has been split into +<CODE>token</CODE>s. There are seven kinds of expansion performed: +<UL> +<LI>brace expansion +<LI>tilde expansion +<LI>parameter and variable expansion +<LI>command substitution +<LI>arithmetic expansion +<LI>word splitting +<LI>filename expansion +</UL> +<P> + +<BLOCKQUOTE><TABLE BORDER=0 CELLSPACING=0> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC29">3.5.1 Brace Expansion</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Expansion of expressions within braces.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC30">3.5.2 Tilde Expansion</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Expansion of the ~ character.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC31">3.5.3 Shell Parameter Expansion</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">How Bash expands variables to their values.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC32">3.5.4 Command Substitution</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Using the output of a command as an argument.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC33">3.5.5 Arithmetic Expansion</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">How to use arithmetic in shell expansions.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC34">3.5.6 Process Substitution</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">A way to write and read to and from a + command.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC35">3.5.7 Word Splitting</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">How the results of expansion are split into separate + arguments.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC36">3.5.8 Filename Expansion</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">A shorthand for specifying filenames matching patterns.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC38">3.5.9 Quote Removal</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">How and when quote characters are removed from + words.</TD></TR> +</TABLE></BLOCKQUOTE> +<P> + +The order of expansions is: brace expansion, tilde expansion, +parameter, variable, and arithmetic expansion and +command substitution +(done in a left-to-right fashion), word splitting, and filename +expansion. +</P><P> + +On systems that can support it, there is an additional expansion +available: <VAR>process substitution</VAR>. This is performed at the +same time as parameter, variable, and arithmetic expansion and +command substitution. +</P><P> + +Only brace expansion, word splitting, and filename expansion +can change the number of words of the expansion; other expansions +expand a single word to a single word. +The only exceptions to this are the expansions of +<CODE>"$@"</CODE> (see section <A HREF="bashref.html#SEC27">3.4.2 Special Parameters</A>) and <CODE>"${<VAR>name</VAR>[@]}"</CODE> +(see section <A HREF="bashref.html#SEC85">6.7 Arrays</A>). +</P><P> + +After all expansions, <CODE>quote removal</CODE> (see section <A HREF="bashref.html#SEC38">3.5.9 Quote Removal</A>) +is performed. +</P><P> + +<A NAME="Brace Expansion"></A> +<HR SIZE="6"> +<A NAME="SEC29"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC28"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC30"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC39"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC28"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC39"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 3.5.1 Brace Expansion </H3> +<!--docid::SEC29::--> +<P> + +Brace expansion is a mechanism by which arbitrary strings may be generated. +This mechanism is similar to +<VAR>filename expansion</VAR> (see section <A HREF="bashref.html#SEC36">3.5.8 Filename Expansion</A>), +but the file names generated need not exist. +Patterns to be brace expanded take the form of an optional <VAR>preamble</VAR>, +followed by either a series of comma-separated strings or a seqeunce expression +between a pair of braces, +followed by an optional <VAR>postscript</VAR>. +The preamble is prefixed to each string contained within the braces, and +the postscript is then appended to each resulting string, expanding left +to right. +</P><P> + +Brace expansions may be nested. +The results of each expanded string are not sorted; left to right order +is preserved. +For example, +<TABLE><tr><td> </td><td class=example><pre>bash$ echo a{d,c,b}e +ade ace abe +</pre></td></tr></table></P><P> + +A sequence expression takes the form <CODE>{<VAR>x</VAR>..<VAR>y</VAR>[..<VAR>incr</VAR>]}</CODE>, +where <VAR>x</VAR> and <VAR>y</VAR> are either integers or single characters, +and <VAR>incr</VAR>, an optional increment, is an integer. +When integers are supplied, the expression expands to each number between +<VAR>x</VAR> and <VAR>y</VAR>, inclusive. +Supplied integers may be prefixed with <SAMP>`0'</SAMP> to force each term to have the +same width. When either <VAR>x</VAR> or <VAR>y</VAR> begins with a zero, the shell +attempts to force all generated terms to contain the same number of digits, +zero-padding where necessary. +When characters are supplied, the expression expands to each character +lexicographically between <VAR>x</VAR> and <VAR>y</VAR>, inclusive. Note that +both <VAR>x</VAR> and <VAR>y</VAR> must be of the same type. +When the increment is supplied, it is used as the difference between +each term. The default increment is 1 or -1 as appropriate. +</P><P> + +Brace expansion is performed before any other expansions, +and any characters special to other expansions are preserved +in the result. It is strictly textual. Bash +does not apply any syntactic interpretation to the context of the +expansion or the text between the braces. +To avoid conflicts with parameter expansion, the string <SAMP>`${'</SAMP> +is not considered eligible for brace expansion. +</P><P> + +A correctly-formed brace expansion must contain unquoted opening +and closing braces, and at least one unquoted comma or a valid +sequence expression. +Any incorrectly formed brace expansion is left unchanged. +</P><P> + +A { or <SAMP>`,'</SAMP> may be quoted with a backslash to prevent its +being considered part of a brace expression. +To avoid conflicts with parameter expansion, the string <SAMP>`${'</SAMP> +is not considered eligible for brace expansion. +</P><P> + +This construct is typically used as shorthand when the common +prefix of the strings to be generated is longer than in the +above example: +<TABLE><tr><td> </td><td class=example><pre>mkdir /usr/local/src/bash/{old,new,dist,bugs} +</pre></td></tr></table>or +<TABLE><tr><td> </td><td class=example><pre>chown root /usr/{ucb/{ex,edit},lib/{ex?.?*,how_ex}} +</pre></td></tr></table></P><P> + +<A NAME="Tilde Expansion"></A> +<HR SIZE="6"> +<A NAME="SEC30"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC29"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC31"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC31"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC28"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC39"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 3.5.2 Tilde Expansion </H3> +<!--docid::SEC30::--> +<P> + +If a word begins with an unquoted tilde character (<SAMP>`~'</SAMP>), all of the +characters up to the first unquoted slash (or all characters, +if there is no unquoted slash) are considered a <VAR>tilde-prefix</VAR>. +If none of the characters in the tilde-prefix are quoted, the +characters in the tilde-prefix following the tilde are treated as a +possible <VAR>login name</VAR>. +If this login name is the null string, the tilde is replaced with the +value of the <CODE>HOME</CODE> shell variable. +If <CODE>HOME</CODE> is unset, the home directory of the user executing the +shell is substituted instead. +Otherwise, the tilde-prefix is replaced with the home directory +associated with the specified login name. +</P><P> + +If the tilde-prefix is <SAMP>`~+'</SAMP>, the value of +the shell variable <CODE>PWD</CODE> replaces the tilde-prefix. +If the tilde-prefix is <SAMP>`~-'</SAMP>, the value of the shell variable +<CODE>OLDPWD</CODE>, if it is set, is substituted. +</P><P> + +If the characters following the tilde in the tilde-prefix consist of a +number <VAR>N</VAR>, optionally prefixed by a <SAMP>`+'</SAMP> or a <SAMP>`-'</SAMP>, +the tilde-prefix is replaced with the +corresponding element from the directory stack, as it would be displayed +by the <CODE>dirs</CODE> builtin invoked with the characters following tilde +in the tilde-prefix as an argument (see section <A HREF="bashref.html#SEC86">6.8 The Directory Stack</A>). +If the tilde-prefix, sans the tilde, consists of a number without a +leading <SAMP>`+'</SAMP> or <SAMP>`-'</SAMP>, <SAMP>`+'</SAMP> is assumed. +</P><P> + +If the login name is invalid, or the tilde expansion fails, the word is +left unchanged. +</P><P> + +Each variable assignment is checked for unquoted tilde-prefixes immediately +following a <SAMP>`:'</SAMP> or the first <SAMP>`='</SAMP>. +In these cases, tilde expansion is also performed. +Consequently, one may use file names with tildes in assignments to +<CODE>PATH</CODE>, <CODE>MAILPATH</CODE>, and <CODE>CDPATH</CODE>, +and the shell assigns the expanded value. +</P><P> + +The following table shows how Bash treats unquoted tilde-prefixes: +</P><P> + +<DL COMPACT> +<DT><CODE>~</CODE> +<DD>The value of <CODE>$HOME</CODE> +<DT><CODE>~/foo</CODE> +<DD><TT>`$HOME/foo'</TT> +<P> + +<DT><CODE>~fred/foo</CODE> +<DD>The subdirectory <CODE>foo</CODE> of the home directory of the user +<CODE>fred</CODE> +<P> + +<DT><CODE>~+/foo</CODE> +<DD><TT>`$PWD/foo'</TT> +<P> + +<DT><CODE>~-/foo</CODE> +<DD><TT>`${OLDPWD-'~-'}/foo'</TT> +<P> + +<DT><CODE>~<VAR>N</VAR></CODE> +<DD>The string that would be displayed by <SAMP>`dirs +<VAR>N</VAR>'</SAMP> +<P> + +<DT><CODE>~+<VAR>N</VAR></CODE> +<DD>The string that would be displayed by <SAMP>`dirs +<VAR>N</VAR>'</SAMP> +<P> + +<DT><CODE>~-<VAR>N</VAR></CODE> +<DD>The string that would be displayed by <SAMP>`dirs -<VAR>N</VAR>'</SAMP> +<P> + +</DL> +<P> + +<A NAME="Shell Parameter Expansion"></A> +<HR SIZE="6"> +<A NAME="SEC31"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC30"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC32"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC32"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC28"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC39"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 3.5.3 Shell Parameter Expansion </H3> +<!--docid::SEC31::--> +<P> + +The <SAMP>`$'</SAMP> character introduces parameter expansion, +command substitution, or arithmetic expansion. The parameter name +or symbol to be expanded may be enclosed in braces, which +are optional but serve to protect the variable to be expanded from +characters immediately following it which could be +interpreted as part of the name. +</P><P> + +When braces are used, the matching ending brace is the first <SAMP>`}'</SAMP> +not escaped by a backslash or within a quoted string, and not within an +embedded arithmetic expansion, command substitution, or parameter +expansion. +</P><P> + +The basic form of parameter expansion is ${<VAR>parameter</VAR>}. +The value of <VAR>parameter</VAR> is substituted. The braces are required +when <VAR>parameter</VAR> +is a positional parameter with more than one digit, +or when <VAR>parameter</VAR> +is followed by a character that is not to be +interpreted as part of its name. +</P><P> + +If the first character of <VAR>parameter</VAR> is an exclamation point (!), +a level of variable indirection is introduced. +Bash uses the value of the variable formed from the rest of +<VAR>parameter</VAR> as the name of the variable; this variable is then +expanded and that value is used in the rest of the substitution, rather +than the value of <VAR>parameter</VAR> itself. +This is known as <CODE>indirect expansion</CODE>. +The exceptions to this are the expansions of ${!<VAR>prefix*</VAR>} +and ${!<VAR>name</VAR>[@]} +described below. +The exclamation point must immediately follow the left brace in order to +introduce indirection. +</P><P> + +In each of the cases below, <VAR>word</VAR> is subject to tilde expansion, +parameter expansion, command substitution, and arithmetic expansion. +</P><P> + +When not performing substring expansion, using the form described +below, Bash tests for a parameter that is unset or null. +Omitting the colon results in a test only for a parameter that is unset. +Put another way, if the colon is included, +the operator tests for both <VAR>parameter</VAR>'s existence and that its value +is not null; if the colon is omitted, the operator tests only for existence. +</P><P> + +<DL COMPACT> + +<DT><CODE>${<VAR>parameter</VAR>:-<VAR>word</VAR>}</CODE> +<DD>If <VAR>parameter</VAR> is unset or null, the expansion of +<VAR>word</VAR> is substituted. Otherwise, the value of +<VAR>parameter</VAR> is substituted. +<P> + +<DT><CODE>${<VAR>parameter</VAR>:=<VAR>word</VAR>}</CODE> +<DD>If <VAR>parameter</VAR> +is unset or null, the expansion of <VAR>word</VAR> +is assigned to <VAR>parameter</VAR>. +The value of <VAR>parameter</VAR> is then substituted. +Positional parameters and special parameters may not be assigned to +in this way. +<P> + +<DT><CODE>${<VAR>parameter</VAR>:?<VAR>word</VAR>}</CODE> +<DD>If <VAR>parameter</VAR> +is null or unset, the expansion of <VAR>word</VAR> (or a message +to that effect if <VAR>word</VAR> +is not present) is written to the standard error and the shell, if it +is not interactive, exits. Otherwise, the value of <VAR>parameter</VAR> is +substituted. +<P> + +<DT><CODE>${<VAR>parameter</VAR>:+<VAR>word</VAR>}</CODE> +<DD>If <VAR>parameter</VAR> +is null or unset, nothing is substituted, otherwise the expansion of +<VAR>word</VAR> is substituted. +<P> + +<DT><CODE>${<VAR>parameter</VAR>:<VAR>offset</VAR>}</CODE> +<DD><DT><CODE>${<VAR>parameter</VAR>:<VAR>offset</VAR>:<VAR>length</VAR>}</CODE> +<DD>Expands to up to <VAR>length</VAR> characters of <VAR>parameter</VAR> +starting at the character specified by <VAR>offset</VAR>. +If <VAR>length</VAR> is omitted, expands to the substring of +<VAR>parameter</VAR> starting at the character specified by <VAR>offset</VAR>. +<VAR>length</VAR> and <VAR>offset</VAR> are arithmetic expressions +(see section <A HREF="bashref.html#SEC83">6.5 Shell Arithmetic</A>). +This is referred to as Substring Expansion. +<P> + +<VAR>length</VAR> must evaluate to a number greater than or equal to zero. +If <VAR>offset</VAR> evaluates to a number less than zero, the value +is used as an offset from the end of the value of <VAR>parameter</VAR>. +If <VAR>parameter</VAR> is <SAMP>`@'</SAMP>, the result is <VAR>length</VAR> positional +parameters beginning at <VAR>offset</VAR>. +If <VAR>parameter</VAR> is an indexed array name subscripted +by <SAMP>`@'</SAMP> or <SAMP>`*'</SAMP>, the result is the <VAR>length</VAR> +members of the array beginning with <CODE>${<VAR>parameter</VAR>[<VAR>offset</VAR>]}</CODE>. +A negative <VAR>offset</VAR> is taken relative to one greater than the maximum +index of the specified array. +Substring expansion applied to an associative array produces undefined +results. +</P><P> + +Note that a negative offset must be separated from the colon by at least +one space to avoid being confused with the <SAMP>`:-'</SAMP> expansion. +Substring indexing is zero-based unless the positional parameters +are used, in which case the indexing starts at 1 by default. +If <VAR>offset</VAR> is 0, and the positional parameters are used, <CODE>$@</CODE> is +prefixed to the list. +</P><P> + +<DT><CODE>${!<VAR>prefix</VAR>*}</CODE> +<DD><DT><CODE>${!<VAR>prefix</VAR>@}</CODE> +<DD>Expands to the names of variables whose names begin with <VAR>prefix</VAR>, +separated by the first character of the <CODE>IFS</CODE> special variable. +When <SAMP>`@'</SAMP> is used and the expansion appears within double quotes, each +variable name expands to a separate word. +<P> + +<DT><CODE>${!<VAR>name</VAR>[@]}</CODE> +<DD><DT><CODE>${!<VAR>name</VAR>[*]}</CODE> +<DD>If <VAR>name</VAR> is an array variable, expands to the list of array indices +(keys) assigned in <VAR>name</VAR>. +If <VAR>name</VAR> is not an array, expands to 0 if <VAR>name</VAR> is set and null +otherwise. +When <SAMP>`@'</SAMP> is used and the expansion appears within double quotes, each +key expands to a separate word. +<P> + +<DT><CODE>${#<VAR>parameter</VAR>}</CODE> +<DD>The length in characters of the expanded value of <VAR>parameter</VAR> is +substituted. +If <VAR>parameter</VAR> is <SAMP>`*'</SAMP> or <SAMP>`@'</SAMP>, the value substituted +is the number of positional parameters. +If <VAR>parameter</VAR> is an array name subscripted by <SAMP>`*'</SAMP> or <SAMP>`@'</SAMP>, +the value substituted is the number of elements in the array. +<P> + +<DT><CODE>${<VAR>parameter</VAR>#<VAR>word</VAR>}</CODE> +<DD><DT><CODE>${<VAR>parameter</VAR>##<VAR>word</VAR>}</CODE> +<DD>The <VAR>word</VAR> +is expanded to produce a pattern just as in filename +expansion (see section <A HREF="bashref.html#SEC36">3.5.8 Filename Expansion</A>). If the pattern matches +the beginning of the expanded value of <VAR>parameter</VAR>, +then the result of the expansion is the expanded value of <VAR>parameter</VAR> +with the shortest matching pattern (the <SAMP>`#'</SAMP> case) or the +longest matching pattern (the <SAMP>`##'</SAMP> case) deleted. +If <VAR>parameter</VAR> is <SAMP>`@'</SAMP> or <SAMP>`*'</SAMP>, +the pattern removal operation is applied to each positional +parameter in turn, and the expansion is the resultant list. +If <VAR>parameter</VAR> is an array variable subscripted with +<SAMP>`@'</SAMP> or <SAMP>`*'</SAMP>, +the pattern removal operation is applied to each member of the +array in turn, and the expansion is the resultant list. +<P> + +<DT><CODE>${<VAR>parameter</VAR>%<VAR>word</VAR>}</CODE> +<DD><DT><CODE>${<VAR>parameter</VAR>%%<VAR>word</VAR>}</CODE> +<DD>The <VAR>word</VAR> is expanded to produce a pattern just as in +filename expansion. +If the pattern matches a trailing portion of the expanded value of +<VAR>parameter</VAR>, then the result of the expansion is the value of +<VAR>parameter</VAR> with the shortest matching pattern (the <SAMP>`%'</SAMP> case) +or the longest matching pattern (the <SAMP>`%%'</SAMP> case) deleted. +If <VAR>parameter</VAR> is <SAMP>`@'</SAMP> or <SAMP>`*'</SAMP>, +the pattern removal operation is applied to each positional +parameter in turn, and the expansion is the resultant list. +If <VAR>parameter</VAR> +is an array variable subscripted with <SAMP>`@'</SAMP> or <SAMP>`*'</SAMP>, +the pattern removal operation is applied to each member of the +array in turn, and the expansion is the resultant list. +<P> + +<DT><CODE>${<VAR>parameter</VAR>/<VAR>pattern</VAR>/<VAR>string</VAR>}</CODE> +<DD><P> + +The <VAR>pattern</VAR> is expanded to produce a pattern just as in +filename expansion. +<VAR>Parameter</VAR> is expanded and the longest match of <VAR>pattern</VAR> +against its value is replaced with <VAR>string</VAR>. +If <VAR>pattern</VAR> begins with <SAMP>`/'</SAMP>, all matches of <VAR>pattern</VAR> are +replaced with <VAR>string</VAR>. Normally only the first match is replaced. +If <VAR>pattern</VAR> begins with <SAMP>`#'</SAMP>, it must match at the beginning +of the expanded value of <VAR>parameter</VAR>. +If <VAR>pattern</VAR> begins with <SAMP>`%'</SAMP>, it must match at the end +of the expanded value of <VAR>parameter</VAR>. +If <VAR>string</VAR> is null, matches of <VAR>pattern</VAR> are deleted +and the <CODE>/</CODE> following <VAR>pattern</VAR> may be omitted. +If <VAR>parameter</VAR> is <SAMP>`@'</SAMP> or <SAMP>`*'</SAMP>, +the substitution operation is applied to each positional +parameter in turn, and the expansion is the resultant list. +If <VAR>parameter</VAR> +is an array variable subscripted with <SAMP>`@'</SAMP> or <SAMP>`*'</SAMP>, +the substitution operation is applied to each member of the +array in turn, and the expansion is the resultant list. +</P><P> + +<DT><CODE>${<VAR>parameter</VAR>^<VAR>pattern</VAR>}</CODE> +<DD><DT><CODE>${<VAR>parameter</VAR>^^<VAR>pattern</VAR>}</CODE> +<DD><DT><CODE>${<VAR>parameter</VAR>,<VAR>pattern</VAR>}</CODE> +<DD><DT><CODE>${<VAR>parameter</VAR>,,<VAR>pattern</VAR>}</CODE> +<DD>This expansion modifies the case of alphabetic characters in <VAR>parameter</VAR>. +The <VAR>pattern</VAR> is expanded to produce a pattern just as in +filename expansion. +The <SAMP>`^'</SAMP> operator converts lowercase letters matching <VAR>pattern</VAR> +to uppercase; the <SAMP>`,'</SAMP> operator converts matching uppercase letters +to lowercase. +The <SAMP>`^^'</SAMP> and <SAMP>`,,'</SAMP> expansions convert each matched character in the +expanded value; the <SAMP>`^'</SAMP> and <SAMP>`,'</SAMP> expansions match and convert only +the first character in the expanded value. +If <VAR>pattern</VAR> is omitted, it is treated like a <SAMP>`?'</SAMP>, which matches +every character. +If <VAR>parameter</VAR> is <SAMP>`@'</SAMP> or <SAMP>`*'</SAMP>, +the case modification operation is applied to each positional +parameter in turn, and the expansion is the resultant list. +If <VAR>parameter</VAR> +is an array variable subscripted with <SAMP>`@'</SAMP> or <SAMP>`*'</SAMP>, +the case modification operation is applied to each member of the +array in turn, and the expansion is the resultant list. +<P> + +</DL> +<P> + +<A NAME="Command Substitution"></A> +<HR SIZE="6"> +<A NAME="SEC32"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC31"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC33"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC33"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC28"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC39"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 3.5.4 Command Substitution </H3> +<!--docid::SEC32::--> +<P> + +Command substitution allows the output of a command to replace +the command itself. +Command substitution occurs when a command is enclosed as follows: +<TABLE><tr><td> </td><td class=example><pre>$(<VAR>command</VAR>) +</pre></td></tr></table>or +<TABLE><tr><td> </td><td class=example><pre>`<VAR>command</VAR>` +</pre></td></tr></table></P><P> + +Bash performs the expansion by executing <VAR>command</VAR> and +replacing the command substitution with the standard output of the +command, with any trailing newlines deleted. +Embedded newlines are not deleted, but they may be removed during +word splitting. +The command substitution <CODE>$(cat <VAR>file</VAR>)</CODE> can be +replaced by the equivalent but faster <CODE>$(< <VAR>file</VAR>)</CODE>. +</P><P> + +When the old-style backquote form of substitution is used, +backslash retains its literal meaning except when followed by +<SAMP>`$'</SAMP>, <SAMP>``'</SAMP>, or <SAMP>`\'</SAMP>. +The first backquote not preceded by a backslash terminates the +command substitution. +When using the <CODE>$(<VAR>command</VAR>)</CODE> form, all characters between +the parentheses make up the command; none are treated specially. +</P><P> + +Command substitutions may be nested. To nest when using the backquoted +form, escape the inner backquotes with backslashes. +</P><P> + +If the substitution appears within double quotes, word splitting and +filename expansion are not performed on the results. +</P><P> + +<A NAME="Arithmetic Expansion"></A> +<HR SIZE="6"> +<A NAME="SEC33"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC32"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC34"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC34"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC28"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC39"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 3.5.5 Arithmetic Expansion </H3> +<!--docid::SEC33::--> +<P> + +Arithmetic expansion allows the evaluation of an arithmetic expression +and the substitution of the result. The format for arithmetic expansion is: +</P><P> + +<TABLE><tr><td> </td><td class=example><pre>$(( <VAR>expression</VAR> )) +</pre></td></tr></table></P><P> + +The expression is treated as if it were within double quotes, but +a double quote inside the parentheses is not treated specially. +All tokens in the expression undergo parameter expansion, command +substitution, and quote removal. +Arithmetic expansions may be nested. +</P><P> + +The evaluation is performed according to the rules listed below +(see section <A HREF="bashref.html#SEC83">6.5 Shell Arithmetic</A>). +If the expression is invalid, Bash prints a message indicating +failure to the standard error and no substitution occurs. +</P><P> + +<A NAME="Process Substitution"></A> +<HR SIZE="6"> +<A NAME="SEC34"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC33"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC35"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC35"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC28"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC39"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 3.5.6 Process Substitution </H3> +<!--docid::SEC34::--> +<P> + +Process substitution is supported on systems that support named +pipes (FIFOs) or the <TT>`/dev/fd'</TT> method of naming open files. +It takes the form of +<TABLE><tr><td> </td><td class=example><pre><(<VAR>list</VAR>) +</pre></td></tr></table>or +<TABLE><tr><td> </td><td class=example><pre>>(<VAR>list</VAR>) +</pre></td></tr></table>The process <VAR>list</VAR> is run with its input or output connected to a +FIFO or some file in <TT>`/dev/fd'</TT>. The name of this file is +passed as an argument to the current command as the result of the +expansion. If the <CODE>>(<VAR>list</VAR>)</CODE> form is used, writing to +the file will provide input for <VAR>list</VAR>. If the +<CODE><(<VAR>list</VAR>)</CODE> form is used, the file passed as an +argument should be read to obtain the output of <VAR>list</VAR>. +Note that no space may appear between the <CODE><</CODE> or <CODE>></CODE> +and the left parenthesis, otherwise the construct would be interpreted +as a redirection. +</P><P> + +When available, process substitution is performed simultaneously with +parameter and variable expansion, command substitution, and arithmetic +expansion. +</P><P> + +<A NAME="Word Splitting"></A> +<HR SIZE="6"> +<A NAME="SEC35"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC34"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC36"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC36"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC28"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC39"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 3.5.7 Word Splitting </H3> +<!--docid::SEC35::--> +<P> + +The shell scans the results of parameter expansion, command substitution, +and arithmetic expansion that did not occur within double quotes for +word splitting. +</P><P> + +The shell treats each character of <CODE>$IFS</CODE> as a delimiter, and splits +the results of the other expansions into words on these characters. +If <CODE>IFS</CODE> is unset, or its value is exactly <CODE><space><tab><newline></CODE>, +the default, then sequences of +<CODE> <space></CODE>, <CODE><tab></CODE>, and <CODE><newline></CODE> +at the beginning and end of the results of the previous +expansions are ignored, and any sequence of <CODE>IFS</CODE> +characters not at the beginning or end serves to delimit words. +If <CODE>IFS</CODE> has a value other than the default, then sequences of +the whitespace characters <CODE>space</CODE> and <CODE>tab</CODE> +are ignored at the beginning and end of the +word, as long as the whitespace character is in the +value of <CODE>IFS</CODE> (an <CODE>IFS</CODE> whitespace character). +Any character in <CODE>IFS</CODE> that is not <CODE>IFS</CODE> +whitespace, along with any adjacent <CODE>IFS</CODE> +whitespace characters, delimits a field. A sequence of <CODE>IFS</CODE> +whitespace characters is also treated as a delimiter. +If the value of <CODE>IFS</CODE> is null, no word splitting occurs. +</P><P> + +Explicit null arguments (<CODE>""</CODE> or <CODE>"</CODE>) are retained. +Unquoted implicit null arguments, resulting from the expansion of +parameters that have no values, are removed. +If a parameter with no value is expanded within double quotes, a +null argument results and is retained. +</P><P> + +Note that if no expansion occurs, no splitting +is performed. +</P><P> + +<A NAME="Filename Expansion"></A> +<HR SIZE="6"> +<A NAME="SEC36"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC35"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC37"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC38"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC28"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC38"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 3.5.8 Filename Expansion </H3> +<!--docid::SEC36::--> +<BLOCKQUOTE><TABLE BORDER=0 CELLSPACING=0> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC37">3.5.8.1 Pattern Matching</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">How the shell matches patterns.</TD></TR> +</TABLE></BLOCKQUOTE> +<A NAME="IDX64"></A> +<A NAME="IDX65"></A> +<A NAME="IDX66"></A> +<A NAME="IDX67"></A> +<P> + +After word splitting, unless the <SAMP>`-f'</SAMP> option has been set +(see section <A HREF="bashref.html#SEC62">4.3.1 The Set Builtin</A>), Bash scans each word for the characters +<SAMP>`*'</SAMP>, <SAMP>`?'</SAMP>, and <SAMP>`['</SAMP>. +If one of these characters appears, then the word is +regarded as a <VAR>pattern</VAR>, +and replaced with an alphabetically sorted list of +file names matching the pattern. If no matching file names are found, +and the shell option <CODE>nullglob</CODE> is disabled, the word is left +unchanged. +If the <CODE>nullglob</CODE> option is set, and no matches are found, the word +is removed. +If the <CODE>failglob</CODE> shell option is set, and no matches are found, +an error message is printed and the command is not executed. +If the shell option <CODE>nocaseglob</CODE> is enabled, the match is performed +without regard to the case of alphabetic characters. +</P><P> + +When a pattern is used for filename expansion, the character <SAMP>`.'</SAMP> +at the start of a filename or immediately following a slash +must be matched explicitly, unless the shell option <CODE>dotglob</CODE> is set. +When matching a file name, the slash character must always be +matched explicitly. +In other cases, the <SAMP>`.'</SAMP> character is not treated specially. +</P><P> + +See the description of <CODE>shopt</CODE> in <A HREF="bashref.html#SEC63">4.3.2 The Shopt Builtin</A>, +for a description of the <CODE>nocaseglob</CODE>, <CODE>nullglob</CODE>, +<CODE>failglob</CODE>, and <CODE>dotglob</CODE> options. +</P><P> + +The <CODE>GLOBIGNORE</CODE> +shell variable may be used to restrict the set of filenames matching a +pattern. If <CODE>GLOBIGNORE</CODE> +is set, each matching filename that also matches one of the patterns in +<CODE>GLOBIGNORE</CODE> is removed from the list of matches. The filenames +<TT>`.'</TT> and <TT>`..'</TT> +are always ignored when <CODE>GLOBIGNORE</CODE> +is set and not null. +However, setting <CODE>GLOBIGNORE</CODE> to a non-null value has the effect of +enabling the <CODE>dotglob</CODE> +shell option, so all other filenames beginning with a +<SAMP>`.'</SAMP> will match. +To get the old behavior of ignoring filenames beginning with a +<SAMP>`.'</SAMP>, make <SAMP>`.*'</SAMP> one of the patterns in <CODE>GLOBIGNORE</CODE>. +The <CODE>dotglob</CODE> option is disabled when <CODE>GLOBIGNORE</CODE> +is unset. +</P><P> + +<A NAME="Pattern Matching"></A> +<HR SIZE="6"> +<A NAME="SEC37"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC36"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC38"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC38"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC36"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC38"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H4> 3.5.8.1 Pattern Matching </H4> +<!--docid::SEC37::--> +<P> + +Any character that appears in a pattern, other than the special pattern +characters described below, matches itself. +The NUL character may not occur in a pattern. +A backslash escapes the following character; the +escaping backslash is discarded when matching. +The special pattern characters must be quoted if they are to be matched +literally. +</P><P> + +The special pattern characters have the following meanings: +<DL COMPACT> +<DT><CODE>*</CODE> +<DD>Matches any string, including the null string. +When the <CODE>globstar</CODE> shell option is enabled, and <SAMP>`*'</SAMP> is used in +a filename expansion context, two adjacent <SAMP>`*'</SAMP>s used as a single +pattern will match all files and zero or more directories and +subdirectories. +If followed by a <SAMP>`/'</SAMP>, two adjacent <SAMP>`*'</SAMP>s will match only +directories and subdirectories. +<DT><CODE>?</CODE> +<DD>Matches any single character. +<DT><CODE>[<small>...</small>]</CODE> +<DD>Matches any one of the enclosed characters. A pair of characters +separated by a hyphen denotes a <VAR>range expression</VAR>; +any character that sorts between those two characters, inclusive, +using the current locale's collating sequence and character set, +is matched. If the first character following the +<SAMP>`['</SAMP> is a <SAMP>`!'</SAMP> or a <SAMP>`^'</SAMP> +then any character not enclosed is matched. A <SAMP>`-'</SAMP> +may be matched by including it as the first or last character +in the set. A <SAMP>`]'</SAMP> may be matched by including it as the first +character in the set. +The sorting order of characters in range expressions is determined by +the current locale and the value of the <CODE>LC_COLLATE</CODE> shell variable, +if set. +<P> + +For example, in the default C locale, <SAMP>`[a-dx-z]'</SAMP> is equivalent to +<SAMP>`[abcdxyz]'</SAMP>. Many locales sort characters in dictionary order, and in +these locales <SAMP>`[a-dx-z]'</SAMP> is typically not equivalent to <SAMP>`[abcdxyz]'</SAMP>; +it might be equivalent to <SAMP>`[aBbCcDdxXyYz]'</SAMP>, for example. To obtain +the traditional interpretation of ranges in bracket expressions, you can +force the use of the C locale by setting the <CODE>LC_COLLATE</CODE> or +<CODE>LC_ALL</CODE> environment variable to the value <SAMP>`C'</SAMP>. +</P><P> + +Within <SAMP>`['</SAMP> and <SAMP>`]'</SAMP>, <VAR>character classes</VAR> can be specified +using the syntax +<CODE>[:</CODE><VAR>class</VAR><CODE>:]</CODE>, where <VAR>class</VAR> is one of the +following classes defined in the POSIX standard: +<TABLE><tr><td> </td><td class=example><pre>alnum alpha ascii blank cntrl digit graph lower +print punct space upper word xdigit +</pre></td></tr></table>A character class matches any character belonging to that class. +The <CODE>word</CODE> character class matches letters, digits, and the character +<SAMP>`_'</SAMP>. +</P><P> + +Within <SAMP>`['</SAMP> and <SAMP>`]'</SAMP>, an <VAR>equivalence class</VAR> can be +specified using the syntax <CODE>[=</CODE><VAR>c</VAR><CODE>=]</CODE>, which +matches all characters with the same collation weight (as defined +by the current locale) as the character <VAR>c</VAR>. +</P><P> + +Within <SAMP>`['</SAMP> and <SAMP>`]'</SAMP>, the syntax <CODE>[.</CODE><VAR>symbol</VAR><CODE>.]</CODE> +matches the collating symbol <VAR>symbol</VAR>. +</DL> +<P> + +If the <CODE>extglob</CODE> shell option is enabled using the <CODE>shopt</CODE> +builtin, several extended pattern matching operators are recognized. +In the following description, a <VAR>pattern-list</VAR> is a list of one +or more patterns separated by a <SAMP>`|'</SAMP>. +Composite patterns may be formed using one or more of the following +sub-patterns: +</P><P> + +<DL COMPACT> +<DT><CODE>?(<VAR>pattern-list</VAR>)</CODE> +<DD>Matches zero or one occurrence of the given patterns. +<P> + +<DT><CODE>*(<VAR>pattern-list</VAR>)</CODE> +<DD>Matches zero or more occurrences of the given patterns. +<P> + +<DT><CODE>+(<VAR>pattern-list</VAR>)</CODE> +<DD>Matches one or more occurrences of the given patterns. +<P> + +<DT><CODE>@(<VAR>pattern-list</VAR>)</CODE> +<DD>Matches one of the given patterns. +<P> + +<DT><CODE>!(<VAR>pattern-list</VAR>)</CODE> +<DD>Matches anything except one of the given patterns. +</DL> +<P> + +<A NAME="Quote Removal"></A> +<HR SIZE="6"> +<A NAME="SEC38"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC37"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC39"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC39"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC28"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC39"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 3.5.9 Quote Removal </H3> +<!--docid::SEC38::--> +<P> + +After the preceding expansions, all unquoted occurrences of the +characters <SAMP>`\'</SAMP>, <SAMP>`''</SAMP>, and <SAMP>`"'</SAMP> that did not +result from one of the above expansions are removed. +</P><P> + +<A NAME="Redirections"></A> +<HR SIZE="6"> +<A NAME="SEC39"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC38"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC40"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC50"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC5"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC50"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H2> 3.6 Redirections </H2> +<!--docid::SEC39::--> +<P> + +Before a command is executed, its input and output +may be <VAR>redirected</VAR> +using a special notation interpreted by the shell. +Redirection may also be used to open and close files for the +current shell execution environment. The following redirection +operators may precede or appear anywhere within a +simple command or may follow a command. +Redirections are processed in the order they appear, from +left to right. +</P><P> + +Each redirection that may be preceded by a file descriptor number +may instead be preceded by a word of the form {<VAR>varname</VAR>}. +In this case, for each redirection operator except +>&- and <&-, the shell will allocate a file descriptor greater +than 10 and assign it to {<VAR>varname</VAR>}. If >&- or <&- is preceded +by {<VAR>varname</VAR>}, the value of <VAR>varname</VAR> defines the file +descriptor to close. +</P><P> + +In the following descriptions, if the file descriptor number is +omitted, and the first character of the redirection operator is +<SAMP>`<'</SAMP>, the redirection refers to the standard input (file +descriptor 0). If the first character of the redirection operator +is <SAMP>`>'</SAMP>, the redirection refers to the standard output (file +descriptor 1). +</P><P> + +The word following the redirection operator in the following +descriptions, unless otherwise noted, is subjected to brace expansion, +tilde expansion, parameter expansion, command substitution, arithmetic +expansion, quote removal, filename expansion, and word splitting. +If it expands to more than one word, Bash reports an error. +</P><P> + +Note that the order of redirections is significant. For example, +the command +<TABLE><tr><td> </td><td class=example><pre>ls > <VAR>dirlist</VAR> 2>&1 +</pre></td></tr></table>directs both standard output (file descriptor 1) and standard error +(file descriptor 2) to the file <VAR>dirlist</VAR>, while the command +<TABLE><tr><td> </td><td class=example><pre>ls 2>&1 > <VAR>dirlist</VAR> +</pre></td></tr></table>directs only the standard output to file <VAR>dirlist</VAR>, +because the standard error was made a copy of the standard output +before the standard output was redirected to <VAR>dirlist</VAR>. +</P><P> + +Bash handles several filenames specially when they are used in +redirections, as described in the following table: +</P><P> + +<DL COMPACT> +<DT><CODE>/dev/fd/<VAR>fd</VAR></CODE> +<DD>If <VAR>fd</VAR> is a valid integer, file descriptor <VAR>fd</VAR> is duplicated. +<P> + +<DT><CODE>/dev/stdin</CODE> +<DD>File descriptor 0 is duplicated. +<P> + +<DT><CODE>/dev/stdout</CODE> +<DD>File descriptor 1 is duplicated. +<P> + +<DT><CODE>/dev/stderr</CODE> +<DD>File descriptor 2 is duplicated. +<P> + +<DT><CODE>/dev/tcp/<VAR>host</VAR>/<VAR>port</VAR></CODE> +<DD>If <VAR>host</VAR> is a valid hostname or Internet address, and <VAR>port</VAR> +is an integer port number or service name, Bash attempts to open a TCP +connection to the corresponding socket. +<P> + +<DT><CODE>/dev/udp/<VAR>host</VAR>/<VAR>port</VAR></CODE> +<DD>If <VAR>host</VAR> is a valid hostname or Internet address, and <VAR>port</VAR> +is an integer port number or service name, Bash attempts to open a UDP +connection to the corresponding socket. +<P> + +</DL> +<P> + +A failure to open or create a file causes the redirection to fail. +</P><P> + +Redirections using file descriptors greater than 9 should be used with +care, as they may conflict with file descriptors the shell uses +internally. +</P><P> + +<HR SIZE="6"> +<A NAME="SEC40"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC39"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC41"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC50"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC39"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC50"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 3.6.1 Redirecting Input </H3> +<!--docid::SEC40::--> +Redirection of input causes the file whose name results from +the expansion of <VAR>word</VAR> +to be opened for reading on file descriptor <CODE>n</CODE>, +or the standard input (file descriptor 0) if <CODE>n</CODE> +is not specified. +<P> + +The general format for redirecting input is: +<TABLE><tr><td> </td><td class=example><pre>[<VAR>n</VAR>]<<VAR>word</VAR> +</pre></td></tr></table></P><P> + +<HR SIZE="6"> +<A NAME="SEC41"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC40"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC42"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC42"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC39"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC50"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 3.6.2 Redirecting Output </H3> +<!--docid::SEC41::--> +Redirection of output causes the file whose name results from +the expansion of <VAR>word</VAR> +to be opened for writing on file descriptor <VAR>n</VAR>, +or the standard output (file descriptor 1) if <VAR>n</VAR> +is not specified. If the file does not exist it is created; +if it does exist it is truncated to zero size. +<P> + +The general format for redirecting output is: +<TABLE><tr><td> </td><td class=example><pre>[<VAR>n</VAR>]>[|]<VAR>word</VAR> +</pre></td></tr></table></P><P> + +If the redirection operator is <SAMP>`>'</SAMP>, and the <CODE>noclobber</CODE> +option to the <CODE>set</CODE> builtin has been enabled, the redirection +will fail if the file whose name results from the expansion of +<VAR>word</VAR> exists and is a regular file. +If the redirection operator is <SAMP>`>|'</SAMP>, or the redirection operator is +<SAMP>`>'</SAMP> and the <CODE>noclobber</CODE> option is not enabled, the redirection +is attempted even if the file named by <VAR>word</VAR> exists. +</P><P> + +<HR SIZE="6"> +<A NAME="SEC42"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC41"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC43"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC43"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC39"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC50"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 3.6.3 Appending Redirected Output </H3> +<!--docid::SEC42::--> +Redirection of output in this fashion +causes the file whose name results from +the expansion of <VAR>word</VAR> +to be opened for appending on file descriptor <VAR>n</VAR>, +or the standard output (file descriptor 1) if <VAR>n</VAR> +is not specified. If the file does not exist it is created. +<P> + +The general format for appending output is: +<TABLE><tr><td> </td><td class=example><pre>[<VAR>n</VAR>]>><VAR>word</VAR> +</pre></td></tr></table></P><P> + +<HR SIZE="6"> +<A NAME="SEC43"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC42"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC44"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC44"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC39"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC50"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 3.6.4 Redirecting Standard Output and Standard Error </H3> +<!--docid::SEC43::--> +This construct allows both the +standard output (file descriptor 1) and +the standard error output (file descriptor 2) +to be redirected to the file whose name is the +expansion of <VAR>word</VAR>. +<P> + +There are two formats for redirecting standard output and +standard error: +<TABLE><tr><td> </td><td class=example><pre>&><VAR>word</VAR> +</pre></td></tr></table>and +<TABLE><tr><td> </td><td class=example><pre>>&<VAR>word</VAR> +</pre></td></tr></table>Of the two forms, the first is preferred. +This is semantically equivalent to +<TABLE><tr><td> </td><td class=example><pre>><VAR>word</VAR> 2>&1 +</pre></td></tr></table></P><P> + +<HR SIZE="6"> +<A NAME="SEC44"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC43"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC45"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC45"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC39"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC50"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 3.6.5 Appending Standard Output and Standard Error </H3> +<!--docid::SEC44::--> +This construct allows both the +standard output (file descriptor 1) and +the standard error output (file descriptor 2) +to be appended to the file whose name is the +expansion of <VAR>word</VAR>. +<P> + +The format for appending standard output and standard error is: +<TABLE><tr><td> </td><td class=example><pre>&>><VAR>word</VAR> +</pre></td></tr></table>This is semantically equivalent to +<TABLE><tr><td> </td><td class=example><pre>>><VAR>word</VAR> 2>&1 +</pre></td></tr></table></P><P> + +<HR SIZE="6"> +<A NAME="SEC45"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC44"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC46"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC46"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC39"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC50"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 3.6.6 Here Documents </H3> +<!--docid::SEC45::--> +This type of redirection instructs the shell to read input from the +current source until a line containing only <VAR>word</VAR> +(with no trailing blanks) is seen. All of +the lines read up to that point are then used as the standard +input for a command. +<P> + +The format of here-documents is: +<TABLE><tr><td> </td><td class=example><pre><<[-]<VAR>word</VAR> + <VAR>here-document</VAR> +<VAR>delimiter</VAR> +</pre></td></tr></table></P><P> + +No parameter expansion, command substitution, arithmetic expansion, +or filename expansion is performed on +<VAR>word</VAR>. If any characters in <VAR>word</VAR> are quoted, the +<VAR>delimiter</VAR> is the result of quote removal on <VAR>word</VAR>, +and the lines in the here-document are not expanded. +If <VAR>word</VAR> is unquoted, +all lines of the here-document are subjected to parameter expansion, +command substitution, and arithmetic expansion. In the latter +case, the character sequence <CODE>\newline</CODE> is ignored, and <SAMP>`\'</SAMP> +must be used to quote the characters +<SAMP>`\'</SAMP>, <SAMP>`$'</SAMP>, and <SAMP>``'</SAMP>. +</P><P> + +If the redirection operator is <SAMP>`<<-'</SAMP>, +then all leading tab characters are stripped from input lines and the +line containing <VAR>delimiter</VAR>. +This allows here-documents within shell scripts to be indented in a +natural fashion. +</P><P> + +<HR SIZE="6"> +<A NAME="SEC46"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC45"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC47"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC47"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC39"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC50"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 3.6.7 Here Strings </H3> +<!--docid::SEC46::--> +A variant of here documents, the format is: +<TABLE><tr><td> </td><td class=example><pre><<< <VAR>word</VAR> +</pre></td></tr></table><P> + +The <VAR>word</VAR> is expanded and supplied to the command on its standard +input. +</P><P> + +<HR SIZE="6"> +<A NAME="SEC47"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC46"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC48"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC48"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC39"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC50"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 3.6.8 Duplicating File Descriptors </H3> +<!--docid::SEC47::--> +The redirection operator +<TABLE><tr><td> </td><td class=example><pre>[<VAR>n</VAR>]<&<VAR>word</VAR> +</pre></td></tr></table>is used to duplicate input file descriptors. +If <VAR>word</VAR> +expands to one or more digits, the file descriptor denoted by <VAR>n</VAR> +is made to be a copy of that file descriptor. +If the digits in <VAR>word</VAR> do not specify a file descriptor open for +input, a redirection error occurs. +If <VAR>word</VAR> +evaluates to <SAMP>`-'</SAMP>, file descriptor <VAR>n</VAR> is closed. If +<VAR>n</VAR> is not specified, the standard input (file descriptor 0) is used. +<P> + +The operator +<TABLE><tr><td> </td><td class=example><pre>[<VAR>n</VAR>]>&<VAR>word</VAR> +</pre></td></tr></table>is used similarly to duplicate output file descriptors. If +<VAR>n</VAR> is not specified, the standard output (file descriptor 1) is used. +If the digits in <VAR>word</VAR> do not specify a file descriptor open for +output, a redirection error occurs. +As a special case, if <VAR>n</VAR> is omitted, and <VAR>word</VAR> does not +expand to one or more digits, the standard output and standard +error are redirected as described previously. +</P><P> + +<HR SIZE="6"> +<A NAME="SEC48"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC47"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC49"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC50"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC39"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC50"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 3.6.9 Moving File Descriptors </H3> +<!--docid::SEC48::--> +The redirection operator +<TABLE><tr><td> </td><td class=example><pre>[<VAR>n</VAR>]<&<VAR>digit</VAR>- +</pre></td></tr></table>moves the file descriptor <VAR>digit</VAR> to file descriptor <VAR>n</VAR>, +or the standard input (file descriptor 0) if <VAR>n</VAR> is not specified. +<VAR>digit</VAR> is closed after being duplicated to <VAR>n</VAR>. +<P> + +Similarly, the redirection operator +<TABLE><tr><td> </td><td class=example><pre>[<VAR>n</VAR>]>&<VAR>digit</VAR>- +</pre></td></tr></table>moves the file descriptor <VAR>digit</VAR> to file descriptor <VAR>n</VAR>, +or the standard output (file descriptor 1) if <VAR>n</VAR> is not specified. +</P><P> + +<HR SIZE="6"> +<A NAME="SEC49"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC48"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC50"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC41"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC39"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC50"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 3.6.10 Opening File Descriptors for Reading and Writing </H3> +<!--docid::SEC49::--> +The redirection operator +<TABLE><tr><td> </td><td class=example><pre>[<VAR>n</VAR>]<><VAR>word</VAR> +</pre></td></tr></table>causes the file whose name is the expansion of <VAR>word</VAR> +to be opened for both reading and writing on file descriptor +<VAR>n</VAR>, or on file descriptor 0 if <VAR>n</VAR> +is not specified. If the file does not exist, it is created. +<P> + +<A NAME="Executing Commands"></A> +<HR SIZE="6"> +<A NAME="SEC50"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC49"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC51"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC57"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC5"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC57"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H2> 3.7 Executing Commands </H2> +<!--docid::SEC50::--> +<P> + +<BLOCKQUOTE><TABLE BORDER=0 CELLSPACING=0> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC51">3.7.1 Simple Command Expansion</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">How Bash expands simple commands before + executing them.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC52">3.7.2 Command Search and Execution</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">How Bash finds commands and runs them.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC53">3.7.3 Command Execution Environment</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">The environment in which Bash + executes commands that are not + shell builtins.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC54">3.7.4 Environment</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">The environment given to a command.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC55">3.7.5 Exit Status</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">The status returned by commands and how Bash + interprets it.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC56">3.7.6 Signals</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">What happens when Bash or a command it runs + receives a signal.</TD></TR> +</TABLE></BLOCKQUOTE> +<P> + +<A NAME="Simple Command Expansion"></A> +<HR SIZE="6"> +<A NAME="SEC51"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC50"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC52"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC57"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC50"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC57"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 3.7.1 Simple Command Expansion </H3> +<!--docid::SEC51::--> +<P> + +When a simple command is executed, the shell performs the following +expansions, assignments, and redirections, from left to right. +</P><P> + +<OL> +<LI> +The words that the parser has marked as variable assignments (those +preceding the command name) and redirections are saved for later +processing. +<P> + +<LI> +The words that are not variable assignments or redirections are +expanded (see section <A HREF="bashref.html#SEC28">3.5 Shell Expansions</A>). +If any words remain after expansion, the first word +is taken to be the name of the command and the remaining words are +the arguments. +<P> + +<LI> +Redirections are performed as described above (see section <A HREF="bashref.html#SEC39">3.6 Redirections</A>). +<P> + +<LI> +The text after the <SAMP>`='</SAMP> in each variable assignment undergoes tilde +expansion, parameter expansion, command substitution, arithmetic expansion, +and quote removal before being assigned to the variable. +</OL> +<P> + +If no command name results, the variable assignments affect the current +shell environment. Otherwise, the variables are added to the environment +of the executed command and do not affect the current shell environment. +If any of the assignments attempts to assign a value to a readonly variable, +an error occurs, and the command exits with a non-zero status. +</P><P> + +If no command name results, redirections are performed, but do not +affect the current shell environment. A redirection error causes the +command to exit with a non-zero status. +</P><P> + +If there is a command name left after expansion, execution proceeds as +described below. Otherwise, the command exits. If one of the expansions +contained a command substitution, the exit status of the command is +the exit status of the last command substitution performed. If there +were no command substitutions, the command exits with a status of zero. +</P><P> + +<A NAME="Command Search and Execution"></A> +<HR SIZE="6"> +<A NAME="SEC52"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC51"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC53"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC53"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC50"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC57"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 3.7.2 Command Search and Execution </H3> +<!--docid::SEC52::--> +<P> + +After a command has been split into words, if it results in a +simple command and an optional list of arguments, the following +actions are taken. +</P><P> + +<OL> +<LI> +If the command name contains no slashes, the shell attempts to +locate it. If there exists a shell function by that name, that +function is invoked as described in <A HREF="bashref.html#SEC24">3.3 Shell Functions</A>. +<P> + +<LI> +If the name does not match a function, the shell searches for +it in the list of shell builtins. If a match is found, that +builtin is invoked. +<P> + +<LI> +If the name is neither a shell function nor a builtin, +and contains no slashes, Bash searches each element of +<CODE>$PATH</CODE> for a directory containing an executable file +by that name. Bash uses a hash table to remember the full +pathnames of executable files to avoid multiple <CODE>PATH</CODE> searches +(see the description of <CODE>hash</CODE> in <A HREF="bashref.html#SEC59">4.1 Bourne Shell Builtins</A>). +A full search of the directories in <CODE>$PATH</CODE> +is performed only if the command is not found in the hash table. +If the search is unsuccessful, the shell searches for a defined shell +function named <CODE>command_not_found_handle</CODE>. +If that function exists, it is invoked with the original command and +the original command's arguments as its arguments, and the function's +exit status becomes the exit status of the shell. +If that function is not defined, the shell prints an error +message and returns an exit status of 127. +<P> + +<LI> +If the search is successful, or if the command name contains +one or more slashes, the shell executes the named program in +a separate execution environment. +Argument 0 is set to the name given, and the remaining arguments +to the command are set to the arguments supplied, if any. +<P> + +<LI> +If this execution fails because the file is not in executable +format, and the file is not a directory, it is assumed to be a +<VAR>shell script</VAR> and the shell executes it as described in +<A HREF="bashref.html#SEC57">3.8 Shell Scripts</A>. +<P> + +<LI> +If the command was not begun asynchronously, the shell waits for +the command to complete and collects its exit status. +<P> + +</OL> +<P> + +<A NAME="Command Execution Environment"></A> +<HR SIZE="6"> +<A NAME="SEC53"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC52"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC54"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC54"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC50"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC57"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 3.7.3 Command Execution Environment </H3> +<!--docid::SEC53::--> +<P> + +The shell has an <VAR>execution environment</VAR>, which consists of the +following: +</P><P> + +<UL> +<LI> +open files inherited by the shell at invocation, as modified by +redirections supplied to the <CODE>exec</CODE> builtin +<P> + +<LI> +the current working directory as set by <CODE>cd</CODE>, <CODE>pushd</CODE>, or +<CODE>popd</CODE>, or inherited by the shell at invocation +<P> + +<LI> +the file creation mode mask as set by <CODE>umask</CODE> or inherited from +the shell's parent +<P> + +<LI> +current traps set by <CODE>trap</CODE> +<P> + +<LI> +shell parameters that are set by variable assignment or with <CODE>set</CODE> +or inherited from the shell's parent in the environment +<P> + +<LI> +shell functions defined during execution or inherited from the shell's +parent in the environment +<P> + +<LI> +options enabled at invocation (either by default or with command-line +arguments) or by <CODE>set</CODE> +<P> + +<LI> +options enabled by <CODE>shopt</CODE> (see section <A HREF="bashref.html#SEC63">4.3.2 The Shopt Builtin</A>) +<P> + +<LI> +shell aliases defined with <CODE>alias</CODE> (see section <A HREF="bashref.html#SEC84">6.6 Aliases</A>) +<P> + +<LI> +various process IDs, including those of background jobs +(see section <A HREF="bashref.html#SEC18">3.2.3 Lists of Commands</A>), the value of <CODE>$$</CODE>, and the value of +<CODE>$PPID</CODE> +<P> + +</UL> +<P> + +When a simple command other than a builtin or shell function +is to be executed, it +is invoked in a separate execution environment that consists of +the following. Unless otherwise noted, the values are inherited +from the shell. +</P><P> + +<UL> +<LI> +the shell's open files, plus any modifications and additions specified +by redirections to the command +<P> + +<LI> +the current working directory +<P> + +<LI> +the file creation mode mask +<P> + +<LI> +shell variables and functions marked for export, along with variables +exported for the command, passed in the environment (see section <A HREF="bashref.html#SEC54">3.7.4 Environment</A>) +<P> + +<LI> +traps caught by the shell are reset to the values inherited from the +shell's parent, and traps ignored by the shell are ignored +<P> + +</UL> +<P> + +A command invoked in this separate environment cannot affect the +shell's execution environment. +</P><P> + +Command substitution, commands grouped with parentheses, +and asynchronous commands are invoked in a +subshell environment that is a duplicate of the shell environment, +except that traps caught by the shell are reset to the values +that the shell inherited from its parent at invocation. Builtin +commands that are invoked as part of a pipeline are also executed +in a subshell environment. Changes made to the subshell environment +cannot affect the shell's execution environment. +</P><P> + +Subshells spawned to execute command substitutions inherit the value of +the <SAMP>`-e'</SAMP> option from the parent shell. When not in POSIX mode, +Bash clears the <SAMP>`-e'</SAMP> option in such subshells. +</P><P> + +If a command is followed by a <SAMP>`&'</SAMP> and job control is not active, the +default standard input for the command is the empty file <TT>`/dev/null'</TT>. +Otherwise, the invoked command inherits the file descriptors of the calling +shell as modified by redirections. +</P><P> + +<A NAME="Environment"></A> +<HR SIZE="6"> +<A NAME="SEC54"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC53"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC55"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC55"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC50"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC57"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 3.7.4 Environment </H3> +<!--docid::SEC54::--> +<P> + +When a program is invoked it is given an array of strings +called the <VAR>environment</VAR>. +This is a list of name-value pairs, of the form <CODE>name=value</CODE>. +</P><P> + +Bash provides several ways to manipulate the environment. +On invocation, the shell scans its own environment and +creates a parameter for each name found, automatically marking +it for <VAR>export</VAR> +to child processes. Executed commands inherit the environment. +The <CODE>export</CODE> and <SAMP>`declare -x'</SAMP> +commands allow parameters and functions to be added to and +deleted from the environment. If the value of a parameter +in the environment is modified, the new value becomes part +of the environment, replacing the old. The environment +inherited by any executed command consists of the shell's +initial environment, whose values may be modified in the shell, +less any pairs removed by the <CODE>unset</CODE> and <SAMP>`export -n'</SAMP> +commands, plus any additions via the <CODE>export</CODE> and +<SAMP>`declare -x'</SAMP> commands. +</P><P> + +The environment for any simple command +or function may be augmented temporarily by prefixing it with +parameter assignments, as described in <A HREF="bashref.html#SEC25">3.4 Shell Parameters</A>. +These assignment statements affect only the environment seen +by that command. +</P><P> + +If the <SAMP>`-k'</SAMP> option is set (see section <A HREF="bashref.html#SEC62">4.3.1 The Set Builtin</A>), then all +parameter assignments are placed in the environment for a command, +not just those that precede the command name. +</P><P> + +When Bash invokes an external command, the variable <SAMP>`$_'</SAMP> +is set to the full path name of the command and passed to that +command in its environment. +</P><P> + +<A NAME="Exit Status"></A> +<HR SIZE="6"> +<A NAME="SEC55"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC54"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC56"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC56"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC50"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC57"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 3.7.5 Exit Status </H3> +<!--docid::SEC55::--> +<P> + +The exit status of an executed command is the value returned by the +<VAR>waitpid</VAR> system call or equivalent function. Exit statuses +fall between 0 and 255, though, as explained below, the shell may +use values above 125 specially. Exit statuses from shell builtins and +compound commands are also limited to this range. Under certain +circumstances, the shell will use special values to indicate specific +failure modes. +</P><P> + +For the shell's purposes, a command which exits with a +zero exit status has succeeded. +A non-zero exit status indicates failure. +This seemingly counter-intuitive scheme is used so there +is one well-defined way to indicate success and a variety of +ways to indicate various failure modes. +When a command terminates on a fatal signal whose number is <VAR>N</VAR>, +Bash uses the value 128+<VAR>N</VAR> as the exit status. +</P><P> + +If a command is not found, the child process created to +execute it returns a status of 127. If a command is found +but is not executable, the return status is 126. +</P><P> + +If a command fails because of an error during expansion or redirection, +the exit status is greater than zero. +</P><P> + +The exit status is used by the Bash conditional commands +(see section <A HREF="bashref.html#SEC21">3.2.4.2 Conditional Constructs</A>) and some of the list +constructs (see section <A HREF="bashref.html#SEC18">3.2.3 Lists of Commands</A>). +</P><P> + +All of the Bash builtins return an exit status of zero if they succeed +and a non-zero status on failure, so they may be used by the +conditional and list constructs. +All builtins return an exit status of 2 to indicate incorrect usage. +</P><P> + +<A NAME="Signals"></A> +<HR SIZE="6"> +<A NAME="SEC56"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC55"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC57"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC57"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC50"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC57"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 3.7.6 Signals </H3> +<!--docid::SEC56::--> +<P> + +When Bash is interactive, in the absence of any traps, it ignores +<CODE>SIGTERM</CODE> (so that <SAMP>`kill 0'</SAMP> does not kill an interactive shell), +and <CODE>SIGINT</CODE> +is caught and handled (so that the <CODE>wait</CODE> builtin is interruptible). +When Bash receives a <CODE>SIGINT</CODE>, it breaks out of any executing loops. +In all cases, Bash ignores <CODE>SIGQUIT</CODE>. +If job control is in effect (see section <A HREF="bashref.html#SEC91">7. Job Control</A>), Bash +ignores <CODE>SIGTTIN</CODE>, <CODE>SIGTTOU</CODE>, and <CODE>SIGTSTP</CODE>. +</P><P> + +Non-builtin commands started by Bash have signal handlers set to the +values inherited by the shell from its parent. +When job control is not in effect, asynchronous commands +ignore <CODE>SIGINT</CODE> and <CODE>SIGQUIT</CODE> in addition to these inherited +handlers. +Commands run as a result of +command substitution ignore the keyboard-generated job control signals +<CODE>SIGTTIN</CODE>, <CODE>SIGTTOU</CODE>, and <CODE>SIGTSTP</CODE>. +</P><P> + +The shell exits by default upon receipt of a <CODE>SIGHUP</CODE>. +Before exiting, an interactive shell resends the <CODE>SIGHUP</CODE> to +all jobs, running or stopped. +Stopped jobs are sent <CODE>SIGCONT</CODE> to ensure that they receive +the <CODE>SIGHUP</CODE>. +To prevent the shell from sending the <CODE>SIGHUP</CODE> signal to a +particular job, it should be removed +from the jobs table with the <CODE>disown</CODE> +builtin (see section <A HREF="bashref.html#SEC93">7.2 Job Control Builtins</A>) or marked +to not receive <CODE>SIGHUP</CODE> using <CODE>disown -h</CODE>. +</P><P> + +If the <CODE>huponexit</CODE> shell option has been set with <CODE>shopt</CODE> +(see section <A HREF="bashref.html#SEC63">4.3.2 The Shopt Builtin</A>), Bash sends a <CODE>SIGHUP</CODE> to all jobs when +an interactive login shell exits. +</P><P> + +If Bash is waiting for a command to complete and receives a signal +for which a trap has been set, the trap will not be executed until +the command completes. +When Bash is waiting for an asynchronous +command via the <CODE>wait</CODE> builtin, the reception of a signal for +which a trap has been set will cause the <CODE>wait</CODE> builtin to return +immediately with an exit status greater than 128, immediately after +which the trap is executed. +</P><P> + +<A NAME="Shell Scripts"></A> +<HR SIZE="6"> +<A NAME="SEC57"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC56"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC58"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC5"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC5"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC58"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H2> 3.8 Shell Scripts </H2> +<!--docid::SEC57::--> +<P> + +A shell script is a text file containing shell commands. When such +a file is used as the first non-option argument when invoking Bash, +and neither the <SAMP>`-c'</SAMP> nor <SAMP>`-s'</SAMP> option is supplied +(see section <A HREF="bashref.html#SEC69">6.1 Invoking Bash</A>), +Bash reads and executes commands from the file, then exits. This +mode of operation creates a non-interactive shell. The shell first +searches for the file in the current directory, and looks in the +directories in <CODE>$PATH</CODE> if not found there. +</P><P> + +When Bash runs +a shell script, it sets the special parameter <CODE>0</CODE> to the name +of the file, rather than the name of the shell, and the positional +parameters are set to the remaining arguments, if any are given. +If no additional arguments are supplied, the positional parameters +are unset. +</P><P> + +A shell script may be made executable by using the <CODE>chmod</CODE> command +to turn on the execute bit. When Bash finds such a file while +searching the <CODE>$PATH</CODE> for a command, it spawns a subshell to +execute it. In other words, executing +<TABLE><tr><td> </td><td class=example><pre>filename <VAR>arguments</VAR> +</pre></td></tr></table>is equivalent to executing +<TABLE><tr><td> </td><td class=example><pre>bash filename <VAR>arguments</VAR> +</pre></td></tr></table></P><P> + +if <CODE>filename</CODE> is an executable shell script. +This subshell reinitializes itself, so that the effect is as if a +new shell had been invoked to interpret the script, with the +exception that the locations of commands remembered by the parent +(see the description of <CODE>hash</CODE> in <A HREF="bashref.html#SEC59">4.1 Bourne Shell Builtins</A>) +are retained by the child. +</P><P> + +Most versions of Unix make this a part of the operating system's command +execution mechanism. If the first line of a script begins with +the two characters <SAMP>`#!'</SAMP>, the remainder of the line specifies +an interpreter for the program. +Thus, you can specify Bash, <CODE>awk</CODE>, Perl, or some other +interpreter and write the rest of the script file in that language. +</P><P> + +The arguments to the interpreter +consist of a single optional argument following the interpreter +name on the first line of the script file, followed by the name of +the script file, followed by the rest of the arguments. Bash +will perform this action on operating systems that do not handle it +themselves. Note that some older versions of Unix limit the interpreter +name and argument to a maximum of 32 characters. +</P><P> + +Bash scripts often begin with <CODE>#! /bin/bash</CODE> (assuming that +Bash has been installed in <TT>`/bin'</TT>), since this ensures that +Bash will be used to interpret the script, even if it is executed +under another shell. +</P><P> + +<A NAME="Shell Builtin Commands"></A> +<HR SIZE="6"> +<A NAME="SEC58"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC57"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC59"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC65"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC65"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H1> 4. Shell Builtin Commands </H1> +<!--docid::SEC58::--> +<P> + +<BLOCKQUOTE><TABLE BORDER=0 CELLSPACING=0> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC59">4.1 Bourne Shell Builtins</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Builtin commands inherited from the Bourne + Shell.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC60">4.2 Bash Builtin Commands</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Table of builtins specific to Bash.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC61">4.3 Modifying Shell Behavior</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Builtins to modify shell attributes and + optional behavior.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC64">4.4 Special Builtins</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Builtin commands classified specially by + POSIX.</TD></TR> +</TABLE></BLOCKQUOTE> +<P> + +Builtin commands are contained within the shell itself. +When the name of a builtin command is used as the first word of +a simple command (see section <A HREF="bashref.html#SEC16">3.2.1 Simple Commands</A>), the shell executes +the command directly, without invoking another program. +Builtin commands are necessary to implement functionality impossible +or inconvenient to obtain with separate utilities. +</P><P> + +This section briefly describes the builtins which Bash inherits from +the Bourne Shell, as well as the builtin commands which are unique +to or have been extended in Bash. +</P><P> + +Several builtin commands are described in other chapters: builtin +commands which provide the Bash interface to the job control +facilities (see section <A HREF="bashref.html#SEC93">7.2 Job Control Builtins</A>), the directory stack +(see section <A HREF="bashref.html#SEC87">6.8.1 Directory Stack Builtins</A>), the command history +(see section <A HREF="bashref.html#SEC121">9.2 Bash History Builtins</A>), and the programmable completion +facilities (see section <A HREF="bashref.html#SEC118">8.7 Programmable Completion Builtins</A>). +</P><P> + +Many of the builtins have been extended by POSIX or Bash. +</P><P> + +Unless otherwise noted, each builtin command documented as accepting +options preceded by <SAMP>`-'</SAMP> accepts <SAMP>`--'</SAMP> +to signify the end of the options. +The <CODE>:</CODE>, <CODE>true</CODE>, <CODE>false</CODE>, and <CODE>test</CODE> +builtins do not accept options and do not treat <SAMP>`--'</SAMP> specially. +The <CODE>exit</CODE>, <CODE>logout</CODE>, <CODE>break</CODE>, <CODE>continue</CODE>, <CODE>let</CODE>, +and <CODE>shift</CODE> builtins accept and process arguments beginning +with <SAMP>`-'</SAMP> without requiring <SAMP>`--'</SAMP>. +Other builtins that accept arguments but are not specified as accepting +options interpret arguments beginning with <SAMP>`-'</SAMP> as invalid options and +require <SAMP>`--'</SAMP> to prevent this interpretation. +</P><P> + +<A NAME="Bourne Shell Builtins"></A> +<HR SIZE="6"> +<A NAME="SEC59"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC58"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC60"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC58"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC58"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC65"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H2> 4.1 Bourne Shell Builtins </H2> +<!--docid::SEC59::--> +<P> + +The following shell builtin commands are inherited from the Bourne Shell. +These commands are implemented as specified by the POSIX standard. +</P><P> + +<DL COMPACT> +<DT><CODE>: (a colon)</CODE> +<DD><A NAME="IDX68"></A> +<TABLE><tr><td> </td><td class=example><pre>: [<VAR>arguments</VAR>] +</pre></td></tr></table>Do nothing beyond expanding <VAR>arguments</VAR> and performing redirections. +The return status is zero. +<P> + +<DT><CODE>. (a period)</CODE> +<DD><A NAME="IDX69"></A> +<TABLE><tr><td> </td><td class=example><pre>. <VAR>filename</VAR> [<VAR>arguments</VAR>] +</pre></td></tr></table>Read and execute commands from the <VAR>filename</VAR> argument in the +current shell context. If <VAR>filename</VAR> does not contain a slash, +the <CODE>PATH</CODE> variable is used to find <VAR>filename</VAR>. +When Bash is not in POSIX mode, the current directory is searched +if <VAR>filename</VAR> is not found in <CODE>$PATH</CODE>. +If any <VAR>arguments</VAR> are supplied, they become the positional +parameters when <VAR>filename</VAR> is executed. Otherwise the positional +parameters are unchanged. +The return status is the exit status of the last command executed, or +zero if no commands are executed. If <VAR>filename</VAR> is not found, or +cannot be read, the return status is non-zero. +This builtin is equivalent to <CODE>source</CODE>. +<P> + +<DT><CODE>break</CODE> +<DD><A NAME="IDX70"></A> +<TABLE><tr><td> </td><td class=example><pre>break [<VAR>n</VAR>] +</pre></td></tr></table>Exit from a <CODE>for</CODE>, <CODE>while</CODE>, <CODE>until</CODE>, or <CODE>select</CODE> loop. +If <VAR>n</VAR> is supplied, the <VAR>n</VAR>th enclosing loop is exited. +<VAR>n</VAR> must be greater than or equal to 1. +The return status is zero unless <VAR>n</VAR> is not greater than or equal to 1. +<P> + +<DT><CODE>cd</CODE> +<DD><A NAME="IDX71"></A> +<TABLE><tr><td> </td><td class=example><pre>cd [-L|-P] [<VAR>directory</VAR>] +</pre></td></tr></table>Change the current working directory to <VAR>directory</VAR>. +If <VAR>directory</VAR> is not given, the value of the <CODE>HOME</CODE> shell +variable is used. +If the shell variable <CODE>CDPATH</CODE> exists, it is used as a search path. +If <VAR>directory</VAR> begins with a slash, <CODE>CDPATH</CODE> is not used. +<P> + +The <SAMP>`-P'</SAMP> option means to not follow symbolic links; symbolic +links are followed by default or with the <SAMP>`-L'</SAMP> option. +If <VAR>directory</VAR> is <SAMP>`-'</SAMP>, it is equivalent to <CODE>$OLDPWD</CODE>. +</P><P> + +If a non-empty directory name from <CODE>CDPATH</CODE> is used, or if +<SAMP>`-'</SAMP> is the first argument, and the directory change is +successful, the absolute pathname of the new working directory is +written to the standard output. +</P><P> + +The return status is zero if the directory is successfully changed, +non-zero otherwise. +</P><P> + +<DT><CODE>continue</CODE> +<DD><A NAME="IDX72"></A> +<TABLE><tr><td> </td><td class=example><pre>continue [<VAR>n</VAR>] +</pre></td></tr></table>Resume the next iteration of an enclosing <CODE>for</CODE>, <CODE>while</CODE>, +<CODE>until</CODE>, or <CODE>select</CODE> loop. +If <VAR>n</VAR> is supplied, the execution of the <VAR>n</VAR>th enclosing loop +is resumed. +<VAR>n</VAR> must be greater than or equal to 1. +The return status is zero unless <VAR>n</VAR> is not greater than or equal to 1. +<P> + +<DT><CODE>eval</CODE> +<DD><A NAME="IDX73"></A> +<TABLE><tr><td> </td><td class=example><pre>eval [<VAR>arguments</VAR>] +</pre></td></tr></table>The arguments are concatenated together into a single command, which is +then read and executed, and its exit status returned as the exit status +of <CODE>eval</CODE>. +If there are no arguments or only empty arguments, the return status is +zero. +<P> + +<DT><CODE>exec</CODE> +<DD><A NAME="IDX74"></A> +<TABLE><tr><td> </td><td class=example><pre>exec [-cl] [-a <VAR>name</VAR>] [<VAR>command</VAR> [<VAR>arguments</VAR>]] +</pre></td></tr></table>If <VAR>command</VAR> +is supplied, it replaces the shell without creating a new process. +If the <SAMP>`-l'</SAMP> option is supplied, the shell places a dash at the +beginning of the zeroth argument passed to <VAR>command</VAR>. +This is what the <CODE>login</CODE> program does. +The <SAMP>`-c'</SAMP> option causes <VAR>command</VAR> to be executed with an empty +environment. +If <SAMP>`-a'</SAMP> is supplied, the shell passes <VAR>name</VAR> as the zeroth +argument to <VAR>command</VAR>. +If no <VAR>command</VAR> is specified, redirections may be used to affect +the current shell environment. If there are no redirection errors, the +return status is zero; otherwise the return status is non-zero. +<P> + +<DT><CODE>exit</CODE> +<DD><A NAME="IDX75"></A> +<TABLE><tr><td> </td><td class=example><pre>exit [<VAR>n</VAR>] +</pre></td></tr></table>Exit the shell, returning a status of <VAR>n</VAR> to the shell's parent. +If <VAR>n</VAR> is omitted, the exit status is that of the last command executed. +Any trap on <CODE>EXIT</CODE> is executed before the shell terminates. +<P> + +<DT><CODE>export</CODE> +<DD><A NAME="IDX76"></A> +<TABLE><tr><td> </td><td class=example><pre>export [-fn] [-p] [<VAR>name</VAR>[=<VAR>value</VAR>]] +</pre></td></tr></table>Mark each <VAR>name</VAR> to be passed to child processes +in the environment. If the <SAMP>`-f'</SAMP> option is supplied, the <VAR>name</VAR>s +refer to shell functions; otherwise the names refer to shell variables. +The <SAMP>`-n'</SAMP> option means to no longer mark each <VAR>name</VAR> for export. +If no <VAR>names</VAR> are supplied, or if the <SAMP>`-p'</SAMP> option is given, a +list of exported names is displayed. +The <SAMP>`-p'</SAMP> option displays output in a form that may be reused as input. +If a variable name is followed by =<VAR>value</VAR>, the value of +the variable is set to <VAR>value</VAR>. +<P> + +The return status is zero unless an invalid option is supplied, one of +the names is not a valid shell variable name, or <SAMP>`-f'</SAMP> is supplied +with a name that is not a shell function. +</P><P> + +<DT><CODE>getopts</CODE> +<DD><A NAME="IDX77"></A> +<TABLE><tr><td> </td><td class=example><pre>getopts <VAR>optstring</VAR> <VAR>name</VAR> [<VAR>args</VAR>] +</pre></td></tr></table><CODE>getopts</CODE> is used by shell scripts to parse positional parameters. +<VAR>optstring</VAR> contains the option characters to be recognized; if a +character is followed by a colon, the option is expected to have an +argument, which should be separated from it by white space. +The colon (<SAMP>`:'</SAMP>) and question mark (<SAMP>`?'</SAMP>) may not be +used as option characters. +Each time it is invoked, <CODE>getopts</CODE> +places the next option in the shell variable <VAR>name</VAR>, initializing +<VAR>name</VAR> if it does not exist, +and the index of the next argument to be processed into the +variable <CODE>OPTIND</CODE>. +<CODE>OPTIND</CODE> is initialized to 1 each time the shell or a shell script +is invoked. +When an option requires an argument, +<CODE>getopts</CODE> places that argument into the variable <CODE>OPTARG</CODE>. +The shell does not reset <CODE>OPTIND</CODE> automatically; it must be manually +reset between multiple calls to <CODE>getopts</CODE> within the same shell +invocation if a new set of parameters is to be used. +<P> + +When the end of options is encountered, <CODE>getopts</CODE> exits with a +return value greater than zero. +<CODE>OPTIND</CODE> is set to the index of the first non-option argument, +and <CODE>name</CODE> is set to <SAMP>`?'</SAMP>. +</P><P> + +<CODE>getopts</CODE> +normally parses the positional parameters, but if more arguments are +given in <VAR>args</VAR>, <CODE>getopts</CODE> parses those instead. +</P><P> + +<CODE>getopts</CODE> can report errors in two ways. If the first character of +<VAR>optstring</VAR> is a colon, <VAR>silent</VAR> +error reporting is used. In normal operation diagnostic messages +are printed when invalid options or missing option arguments are +encountered. +If the variable <CODE>OPTERR</CODE> +is set to 0, no error messages will be displayed, even if the first +character of <CODE>optstring</CODE> is not a colon. +</P><P> + +If an invalid option is seen, +<CODE>getopts</CODE> places <SAMP>`?'</SAMP> into <VAR>name</VAR> and, if not silent, +prints an error message and unsets <CODE>OPTARG</CODE>. +If <CODE>getopts</CODE> is silent, the option character found is placed in +<CODE>OPTARG</CODE> and no diagnostic message is printed. +</P><P> + +If a required argument is not found, and <CODE>getopts</CODE> +is not silent, a question mark (<SAMP>`?'</SAMP>) is placed in <VAR>name</VAR>, +<CODE>OPTARG</CODE> is unset, and a diagnostic message is printed. +If <CODE>getopts</CODE> is silent, then a colon (<SAMP>`:'</SAMP>) is placed in +<VAR>name</VAR> and <CODE>OPTARG</CODE> is set to the option character found. +</P><P> + +<DT><CODE>hash</CODE> +<DD><A NAME="IDX78"></A> +<TABLE><tr><td> </td><td class=example><pre>hash [-r] [-p <VAR>filename</VAR>] [-dt] [<VAR>name</VAR>] +</pre></td></tr></table>Remember the full pathnames of commands specified as <VAR>name</VAR> arguments, +so they need not be searched for on subsequent invocations. +The commands are found by searching through the directories listed in +<CODE>$PATH</CODE>. +The <SAMP>`-p'</SAMP> option inhibits the path search, and <VAR>filename</VAR> is +used as the location of <VAR>name</VAR>. +The <SAMP>`-r'</SAMP> option causes the shell to forget all remembered locations. +The <SAMP>`-d'</SAMP> option causes the shell to forget the remembered location +of each <VAR>name</VAR>. +If the <SAMP>`-t'</SAMP> option is supplied, the full pathname to which each +<VAR>name</VAR> corresponds is printed. If multiple <VAR>name</VAR> arguments are +supplied with <SAMP>`-t'</SAMP> the <VAR>name</VAR> is printed before the hashed +full pathname. +The <SAMP>`-l'</SAMP> option causes output to be displayed in a format +that may be reused as input. +If no arguments are given, or if only <SAMP>`-l'</SAMP> is supplied, +information about remembered commands is printed. +The return status is zero unless a <VAR>name</VAR> is not found or an invalid +option is supplied. +<P> + +<DT><CODE>pwd</CODE> +<DD><A NAME="IDX79"></A> +<TABLE><tr><td> </td><td class=example><pre>pwd [-LP] +</pre></td></tr></table>Print the absolute pathname of the current working directory. +If the <SAMP>`-P'</SAMP> option is supplied, the pathname printed will not +contain symbolic links. +If the <SAMP>`-L'</SAMP> option is supplied, the pathname printed may contain +symbolic links. +The return status is zero unless an error is encountered while +determining the name of the current directory or an invalid option +is supplied. +<P> + +<DT><CODE>readonly</CODE> +<DD><A NAME="IDX80"></A> +<TABLE><tr><td> </td><td class=example><pre>readonly [-aApf] [<VAR>name</VAR>[=<VAR>value</VAR>]] <small>...</small> +</pre></td></tr></table>Mark each <VAR>name</VAR> as readonly. +The values of these names may not be changed by subsequent assignment. +If the <SAMP>`-f'</SAMP> option is supplied, each <VAR>name</VAR> refers to a shell +function. +The <SAMP>`-a'</SAMP> option means each <VAR>name</VAR> refers to an indexed +array variable; the <SAMP>`-A'</SAMP> option means each <VAR>name</VAR> refers +to an associative array variable. +If no <VAR>name</VAR> arguments are given, or if the <SAMP>`-p'</SAMP> +option is supplied, a list of all readonly names is printed. +The <SAMP>`-p'</SAMP> option causes output to be displayed in a format that +may be reused as input. +If a variable name is followed by =<VAR>value</VAR>, the value of +the variable is set to <VAR>value</VAR>. +The return status is zero unless an invalid option is supplied, one of +the <VAR>name</VAR> arguments is not a valid shell variable or function name, +or the <SAMP>`-f'</SAMP> option is supplied with a name that is not a shell function. +<P> + +<DT><CODE>return</CODE> +<DD><A NAME="IDX81"></A> +<TABLE><tr><td> </td><td class=example><pre>return [<VAR>n</VAR>] +</pre></td></tr></table>Cause a shell function to exit with the return value <VAR>n</VAR>. +If <VAR>n</VAR> is not supplied, the return value is the exit status of the +last command executed in the function. +This may also be used to terminate execution of a script being executed +with the <CODE>.</CODE> (or <CODE>source</CODE>) builtin, returning either <VAR>n</VAR> or +the exit status of the last command executed within the script as the exit +status of the script. +Any command associated with the <CODE>RETURN</CODE> trap is executed +before execution resumes after the function or script. +The return status is non-zero if <CODE>return</CODE> is used outside a function +and not during the execution of a script by <CODE>.</CODE> or <CODE>source</CODE>. +<P> + +<DT><CODE>shift</CODE> +<DD><A NAME="IDX82"></A> +<TABLE><tr><td> </td><td class=example><pre>shift [<VAR>n</VAR>] +</pre></td></tr></table>Shift the positional parameters to the left by <VAR>n</VAR>. +The positional parameters from <VAR>n</VAR>+1 <small>...</small> <CODE>$#</CODE> are +renamed to <CODE>$1</CODE> <small>...</small> <CODE>$#</CODE>-<VAR>n</VAR>. +Parameters represented by the numbers <CODE>$#</CODE> to <CODE>$#</CODE>-<VAR>n</VAR>+1 +are unset. +<VAR>n</VAR> must be a non-negative number less than or equal to <CODE>$#</CODE>. +If <VAR>n</VAR> is zero or greater than <CODE>$#</CODE>, the positional parameters +are not changed. +If <VAR>n</VAR> is not supplied, it is assumed to be 1. +The return status is zero unless <VAR>n</VAR> is greater than <CODE>$#</CODE> or +less than zero, non-zero otherwise. +<P> + +<DT><CODE>test</CODE> +<DD><DT><CODE>[</CODE> +<DD><A NAME="IDX83"></A> +<A NAME="IDX84"></A> +Evaluate a conditional expression <VAR>expr</VAR>. +Each operator and operand must be a separate argument. +Expressions are composed of the primaries described below in +<A HREF="bashref.html#SEC82">6.4 Bash Conditional Expressions</A>. +<CODE>test</CODE> does not accept any options, nor does it accept and ignore +an argument of <SAMP>`--'</SAMP> as signifying the end of options. +<P> + +When the <CODE>[</CODE> form is used, the last argument to the command must +be a <CODE>]</CODE>. +</P><P> + +Expressions may be combined using the following operators, listed in +decreasing order of precedence. +The evaluation depends on the number of arguments; see below. +</P><P> + +<DL COMPACT> +<DT><CODE>! <VAR>expr</VAR></CODE> +<DD>True if <VAR>expr</VAR> is false. +<P> + +<DT><CODE>( <VAR>expr</VAR> )</CODE> +<DD>Returns the value of <VAR>expr</VAR>. +This may be used to override the normal precedence of operators. +<P> + +<DT><CODE><VAR>expr1</VAR> -a <VAR>expr2</VAR></CODE> +<DD>True if both <VAR>expr1</VAR> and <VAR>expr2</VAR> are true. +<P> + +<DT><CODE><VAR>expr1</VAR> -o <VAR>expr2</VAR></CODE> +<DD>True if either <VAR>expr1</VAR> or <VAR>expr2</VAR> is true. +</DL> +<P> + +The <CODE>test</CODE> and <CODE>[</CODE> builtins evaluate conditional +expressions using a set of rules based on the number of arguments. +</P><P> + +<DL COMPACT> +<DT>0 arguments +<DD>The expression is false. +<P> + +<DT>1 argument +<DD>The expression is true if and only if the argument is not null. +<P> + +<DT>2 arguments +<DD>If the first argument is <SAMP>`!'</SAMP>, the expression is true if and +only if the second argument is null. +If the first argument is one of the unary conditional operators +(see section <A HREF="bashref.html#SEC82">6.4 Bash Conditional Expressions</A>), the expression +is true if the unary test is true. +If the first argument is not a valid unary operator, the expression is +false. +<P> + +<DT>3 arguments +<DD>If the second argument is one of the binary conditional +operators (see section <A HREF="bashref.html#SEC82">6.4 Bash Conditional Expressions</A>), the +result of the expression is the result of the binary test using the +first and third arguments as operands. +The <SAMP>`-a'</SAMP> and <SAMP>`-o'</SAMP> operators are considered binary operators +when there are three arguments. +If the first argument is <SAMP>`!'</SAMP>, the value is the negation of +the two-argument test using the second and third arguments. +If the first argument is exactly <SAMP>`('</SAMP> and the third argument is +exactly <SAMP>`)'</SAMP>, the result is the one-argument test of the second +argument. +Otherwise, the expression is false. +<P> + +<DT>4 arguments +<DD>If the first argument is <SAMP>`!'</SAMP>, the result is the negation of +the three-argument expression composed of the remaining arguments. +Otherwise, the expression is parsed and evaluated according to +precedence using the rules listed above. +<P> + +<DT>5 or more arguments +<DD>The expression is parsed and evaluated according to precedence +using the rules listed above. +</DL> +<P> + +<DT><CODE>times</CODE> +<DD><A NAME="IDX85"></A> +<TABLE><tr><td> </td><td class=example><pre>times +</pre></td></tr></table>Print out the user and system times used by the shell and its children. +The return status is zero. +<P> + +<DT><CODE>trap</CODE> +<DD><A NAME="IDX86"></A> +<TABLE><tr><td> </td><td class=example><pre>trap [-lp] [<VAR>arg</VAR>] [<VAR>sigspec</VAR> <small>...</small>] +</pre></td></tr></table>The commands in <VAR>arg</VAR> are to be read and executed when the +shell receives signal <VAR>sigspec</VAR>. If <VAR>arg</VAR> is absent (and +there is a single <VAR>sigspec</VAR>) or +equal to <SAMP>`-'</SAMP>, each specified signal's disposition is reset +to the value it had when the shell was started. +If <VAR>arg</VAR> is the null string, then the signal specified by +each <VAR>sigspec</VAR> is ignored by the shell and commands it invokes. +If <VAR>arg</VAR> is not present and <SAMP>`-p'</SAMP> has been supplied, +the shell displays the trap commands associated with each <VAR>sigspec</VAR>. +If no arguments are supplied, or +only <SAMP>`-p'</SAMP> is given, <CODE>trap</CODE> prints the list of commands +associated with each signal number in a form that may be reused as +shell input. +The <SAMP>`-l'</SAMP> option causes the shell to print a list of signal names +and their corresponding numbers. +Each <VAR>sigspec</VAR> is either a signal name or a signal number. +Signal names are case insensitive and the <CODE>SIG</CODE> prefix is optional. +<P> + +If a <VAR>sigspec</VAR> +is <CODE>0</CODE> or <CODE>EXIT</CODE>, <VAR>arg</VAR> is executed when the shell exits. +If a <VAR>sigspec</VAR> is <CODE>DEBUG</CODE>, the command <VAR>arg</VAR> is executed +before every simple command, <CODE>for</CODE> command, <CODE>case</CODE> command, +<CODE>select</CODE> command, every arithmetic <CODE>for</CODE> command, and before +the first command executes in a shell function. +Refer to the description of the <CODE>extdebug</CODE> option to the +<CODE>shopt</CODE> builtin (see section <A HREF="bashref.html#SEC63">4.3.2 The Shopt Builtin</A>) for details of its +effect on the <CODE>DEBUG</CODE> trap. +If a <VAR>sigspec</VAR> is <CODE>RETURN</CODE>, the command <VAR>arg</VAR> is executed +each time a shell function or a script executed with the <CODE>.</CODE> or +<CODE>source</CODE> builtins finishes executing. +</P><P> + +If a <VAR>sigspec</VAR> is <CODE>ERR</CODE>, the command <VAR>arg</VAR> +is executed whenever a simple command has a non-zero exit status, +subject to the following conditions. +The <CODE>ERR</CODE> trap is not executed if the failed command is part of the +command list immediately following an <CODE>until</CODE> or <CODE>while</CODE> keyword, +part of the test following the <CODE>if</CODE> or <CODE>elif</CODE> reserved words, +part of a command executed in a <CODE>&&</CODE> or <CODE>||</CODE> list, +or if the command's return +status is being inverted using <CODE>!</CODE>. +These are the same conditions obeyed by the <CODE>errexit</CODE> option. +</P><P> + +Signals ignored upon entry to the shell cannot be trapped or reset. +Trapped signals that are not being ignored are reset to their original +values in a subshell or subshell environment when one is created. +</P><P> + +The return status is zero unless a <VAR>sigspec</VAR> does not specify a +valid signal. +</P><P> + +<DT><CODE>umask</CODE> +<DD><A NAME="IDX87"></A> +<TABLE><tr><td> </td><td class=example><pre>umask [-p] [-S] [<VAR>mode</VAR>] +</pre></td></tr></table>Set the shell process's file creation mask to <VAR>mode</VAR>. If +<VAR>mode</VAR> begins with a digit, it is interpreted as an octal number; +if not, it is interpreted as a symbolic mode mask similar +to that accepted by the <CODE>chmod</CODE> command. If <VAR>mode</VAR> is +omitted, the current value of the mask is printed. If the <SAMP>`-S'</SAMP> +option is supplied without a <VAR>mode</VAR> argument, the mask is printed +in a symbolic format. +If the <SAMP>`-p'</SAMP> option is supplied, and <VAR>mode</VAR> +is omitted, the output is in a form that may be reused as input. +The return status is zero if the mode is successfully changed or if +no <VAR>mode</VAR> argument is supplied, and non-zero otherwise. +<P> + +Note that when the mode is interpreted as an octal number, each number +of the umask is subtracted from <CODE>7</CODE>. Thus, a umask of <CODE>022</CODE> +results in permissions of <CODE>755</CODE>. +</P><P> + +<DT><CODE>unset</CODE> +<DD><A NAME="IDX88"></A> +<TABLE><tr><td> </td><td class=example><pre>unset [-fv] [<VAR>name</VAR>] +</pre></td></tr></table>Each variable or function <VAR>name</VAR> is removed. +If no options are supplied, or the <SAMP>`-v'</SAMP> option is given, each +<VAR>name</VAR> refers to a shell variable. +If the <SAMP>`-f'</SAMP> option is given, the <VAR>name</VAR>s refer to shell +functions, and the function definition is removed. +Readonly variables and functions may not be unset. +The return status is zero unless a <VAR>name</VAR> is readonly. +</DL> +<P> + +<A NAME="Bash Builtins"></A> +<HR SIZE="6"> +<A NAME="SEC60"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC59"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC61"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC61"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC58"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC65"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H2> 4.2 Bash Builtin Commands </H2> +<!--docid::SEC60::--> +<P> + +This section describes builtin commands which are unique to +or have been extended in Bash. +Some of these commands are specified in the POSIX standard. +</P><P> + +<DL COMPACT> + +<DT><CODE>alias</CODE> +<DD><A NAME="IDX89"></A> +<TABLE><tr><td> </td><td class=example><pre>alias [<CODE>-p</CODE>] [<VAR>name</VAR>[=<VAR>value</VAR>] <small>...</small>] +</pre></td></tr></table><P> + +Without arguments or with the <SAMP>`-p'</SAMP> option, <CODE>alias</CODE> prints +the list of aliases on the standard output in a form that allows +them to be reused as input. +If arguments are supplied, an alias is defined for each <VAR>name</VAR> +whose <VAR>value</VAR> is given. If no <VAR>value</VAR> is given, the name +and value of the alias is printed. +Aliases are described in <A HREF="bashref.html#SEC84">6.6 Aliases</A>. +</P><P> + +<DT><CODE>bind</CODE> +<DD><A NAME="IDX90"></A> +<TABLE><tr><td> </td><td class=example><pre>bind [-m <VAR>keymap</VAR>] [-lpsvPSV] +bind [-m <VAR>keymap</VAR>] [-q <VAR>function</VAR>] [-u <VAR>function</VAR>] [-r <VAR>keyseq</VAR>] +bind [-m <VAR>keymap</VAR>] -f <VAR>filename</VAR> +bind [-m <VAR>keymap</VAR>] -x <VAR>keyseq:shell-command</VAR> +bind [-m <VAR>keymap</VAR>] <VAR>keyseq:function-name</VAR> +bind <VAR>readline-command</VAR> +</pre></td></tr></table><P> + +Display current Readline (see section <A HREF="bashref.html#SEC95">8. Command Line Editing</A>) +key and function bindings, +bind a key sequence to a Readline function or macro, +or set a Readline variable. +Each non-option argument is a command as it would appear in a +Readline initialization file (see section <A HREF="bashref.html#SEC103">8.3 Readline Init File</A>), +but each binding or command must be passed as a separate argument; e.g., +<SAMP>`"\C-x\C-r":re-read-init-file'</SAMP>. +</P><P> + +Options, if supplied, have the following meanings: +</P><P> + +<DL COMPACT> +<DT><CODE>-m <VAR>keymap</VAR></CODE> +<DD>Use <VAR>keymap</VAR> as the keymap to be affected by +the subsequent bindings. Acceptable <VAR>keymap</VAR> +names are +<CODE>emacs</CODE>, +<CODE>emacs-standard</CODE>, +<CODE>emacs-meta</CODE>, +<CODE>emacs-ctlx</CODE>, +<CODE>vi</CODE>, +<CODE>vi-move</CODE>, +<CODE>vi-command</CODE>, and +<CODE>vi-insert</CODE>. +<CODE>vi</CODE> is equivalent to <CODE>vi-command</CODE>; +<CODE>emacs</CODE> is equivalent to <CODE>emacs-standard</CODE>. +<P> + +<DT><CODE>-l</CODE> +<DD>List the names of all Readline functions. +<P> + +<DT><CODE>-p</CODE> +<DD>Display Readline function names and bindings in such a way that they +can be used as input or in a Readline initialization file. +<P> + +<DT><CODE>-P</CODE> +<DD>List current Readline function names and bindings. +<P> + +<DT><CODE>-v</CODE> +<DD>Display Readline variable names and values in such a way that they +can be used as input or in a Readline initialization file. +<P> + +<DT><CODE>-V</CODE> +<DD>List current Readline variable names and values. +<P> + +<DT><CODE>-s</CODE> +<DD>Display Readline key sequences bound to macros and the strings they output +in such a way that they can be used as input or in a Readline +initialization file. +<P> + +<DT><CODE>-S</CODE> +<DD>Display Readline key sequences bound to macros and the strings they output. +<P> + +<DT><CODE>-f <VAR>filename</VAR></CODE> +<DD>Read key bindings from <VAR>filename</VAR>. +<P> + +<DT><CODE>-q <VAR>function</VAR></CODE> +<DD>Query about which keys invoke the named <VAR>function</VAR>. +<P> + +<DT><CODE>-u <VAR>function</VAR></CODE> +<DD>Unbind all keys bound to the named <VAR>function</VAR>. +<P> + +<DT><CODE>-r <VAR>keyseq</VAR></CODE> +<DD>Remove any current binding for <VAR>keyseq</VAR>. +<P> + +<DT><CODE>-x <VAR>keyseq:shell-command</VAR></CODE> +<DD>Cause <VAR>shell-command</VAR> to be executed whenever <VAR>keyseq</VAR> is +entered. +When <VAR>shell-command</VAR> is executed, the shell sets the +<CODE>READLINE_LINE</CODE> variable to the contents of the Readline line +buffer and the <CODE>READLINE_POINT</CODE> variable to the current location +of the insertion point. +If the executed command changes the value of <CODE>READLINE_LINE</CODE> or +<CODE>READLINE_POINT</CODE>, those new values will be reflected in the +editing state. +</DL> +<P> + +The return status is zero unless an invalid option is supplied or an +error occurs. +</P><P> + +<DT><CODE>builtin</CODE> +<DD><A NAME="IDX91"></A> +<TABLE><tr><td> </td><td class=example><pre>builtin [<VAR>shell-builtin</VAR> [<VAR>args</VAR>]] +</pre></td></tr></table>Run a shell builtin, passing it <VAR>args</VAR>, and return its exit status. +This is useful when defining a shell function with the same +name as a shell builtin, retaining the functionality of the builtin within +the function. +The return status is non-zero if <VAR>shell-builtin</VAR> is not a shell +builtin command. +<P> + +<DT><CODE>caller</CODE> +<DD><A NAME="IDX92"></A> +<TABLE><tr><td> </td><td class=example><pre>caller [<VAR>expr</VAR>] +</pre></td></tr></table>Returns the context of any active subroutine call (a shell function or +a script executed with the <CODE>.</CODE> or <CODE>source</CODE> builtins). +<P> + +Without <VAR>expr</VAR>, <CODE>caller</CODE> displays the line number and source +filename of the current subroutine call. +If a non-negative integer is supplied as <VAR>expr</VAR>, <CODE>caller</CODE> +displays the line number, subroutine name, and source file corresponding +to that position in the current execution call stack. This extra +information may be used, for example, to print a stack trace. The +current frame is frame 0. +</P><P> + +The return value is 0 unless the shell is not executing a subroutine +call or <VAR>expr</VAR> does not correspond to a valid position in the +call stack. +</P><P> + +<DT><CODE>command</CODE> +<DD><A NAME="IDX93"></A> +<TABLE><tr><td> </td><td class=example><pre>command [-pVv] <VAR>command</VAR> [<VAR>arguments</VAR> <small>...</small>] +</pre></td></tr></table>Runs <VAR>command</VAR> with <VAR>arguments</VAR> ignoring any shell function +named <VAR>command</VAR>. +Only shell builtin commands or commands found by searching the +<CODE>PATH</CODE> are executed. +If there is a shell function named <CODE>ls</CODE>, running <SAMP>`command ls'</SAMP> +within the function will execute the external command <CODE>ls</CODE> +instead of calling the function recursively. +The <SAMP>`-p'</SAMP> option means to use a default value for <CODE>PATH</CODE> +that is guaranteed to find all of the standard utilities. +The return status in this case is 127 if <VAR>command</VAR> cannot be +found or an error occurred, and the exit status of <VAR>command</VAR> +otherwise. +<P> + +If either the <SAMP>`-V'</SAMP> or <SAMP>`-v'</SAMP> option is supplied, a +description of <VAR>command</VAR> is printed. The <SAMP>`-v'</SAMP> option +causes a single word indicating the command or file name used to +invoke <VAR>command</VAR> to be displayed; the <SAMP>`-V'</SAMP> option produces +a more verbose description. In this case, the return status is +zero if <VAR>command</VAR> is found, and non-zero if not. +</P><P> + +<DT><CODE>declare</CODE> +<DD><A NAME="IDX94"></A> +<TABLE><tr><td> </td><td class=example><pre>declare [-aAfFilrtux] [-p] [<VAR>name</VAR>[=<VAR>value</VAR>] <small>...</small>] +</pre></td></tr></table><P> + +Declare variables and give them attributes. If no <VAR>name</VAR>s +are given, then display the values of variables instead. +</P><P> + +The <SAMP>`-p'</SAMP> option will display the attributes and values of each +<VAR>name</VAR>. +When <SAMP>`-p'</SAMP> is used with <VAR>name</VAR> arguments, additional options +are ignored. +</P><P> + +When <SAMP>`-p'</SAMP> is supplied without <VAR>name</VAR> arguments, <CODE>declare</CODE> +will display the attributes and values of all variables having the +attributes specified by the additional options. +If no other options are supplied with <SAMP>`-p'</SAMP>, <CODE>declare</CODE> will +display the attributes and values of all shell variables. The <SAMP>`-f'</SAMP> +option will restrict the display to shell functions. +</P><P> + +The <SAMP>`-F'</SAMP> option inhibits the display of function definitions; +only the function name and attributes are printed. +If the <CODE>extdebug</CODE> shell option is enabled using <CODE>shopt</CODE> +(see section <A HREF="bashref.html#SEC63">4.3.2 The Shopt Builtin</A>), the source file name and line number where +the function is defined are displayed as well. +<SAMP>`-F'</SAMP> implies <SAMP>`-f'</SAMP>. +The following options can be used to restrict output to variables with +the specified attributes or to give variables attributes: +</P><P> + +<DL COMPACT> +<DT><CODE>-a</CODE> +<DD>Each <VAR>name</VAR> is an indexed array variable (see section <A HREF="bashref.html#SEC85">6.7 Arrays</A>). +<P> + +<DT><CODE>-A</CODE> +<DD>Each <VAR>name</VAR> is an associative array variable (see section <A HREF="bashref.html#SEC85">6.7 Arrays</A>). +<P> + +<DT><CODE>-f</CODE> +<DD>Use function names only. +<P> + +<DT><CODE>-i</CODE> +<DD>The variable is to be treated as +an integer; arithmetic evaluation (see section <A HREF="bashref.html#SEC83">6.5 Shell Arithmetic</A>) is +performed when the variable is assigned a value. +<P> + +<DT><CODE>-l</CODE> +<DD>When the variable is assigned a value, all upper-case characters are +converted to lower-case. +The upper-case attribute is disabled. +<P> + +<DT><CODE>-r</CODE> +<DD>Make <VAR>name</VAR>s readonly. These names cannot then be assigned values +by subsequent assignment statements or unset. +<P> + +<DT><CODE>-t</CODE> +<DD>Give each <VAR>name</VAR> the <CODE>trace</CODE> attribute. +Traced functions inherit the <CODE>DEBUG</CODE> and <CODE>RETURN</CODE> traps from +the calling shell. +The trace attribute has no special meaning for variables. +<P> + +<DT><CODE>-u</CODE> +<DD>When the variable is assigned a value, all lower-case characters are +converted to upper-case. +The lower-case attribute is disabled. +<P> + +<DT><CODE>-x</CODE> +<DD>Mark each <VAR>name</VAR> for export to subsequent commands via +the environment. +</DL> +<P> + +Using <SAMP>`+'</SAMP> instead of <SAMP>`-'</SAMP> turns off the attribute instead, +with the exceptions that <SAMP>`+a'</SAMP> +may not be used to destroy an array variable and <SAMP>`+r'</SAMP> will not +remove the readonly attribute. +When used in a function, <CODE>declare</CODE> makes each <VAR>name</VAR> local, +as with the <CODE>local</CODE> command. If a variable name is followed by +=<VAR>value</VAR>, the value of the variable is set to <VAR>value</VAR>. +</P><P> + +The return status is zero unless an invalid option is encountered, +an attempt is made to define a function using <SAMP>`-f foo=bar'</SAMP>, +an attempt is made to assign a value to a readonly variable, +an attempt is made to assign a value to an array variable without +using the compound assignment syntax (see section <A HREF="bashref.html#SEC85">6.7 Arrays</A>), +one of the <VAR>names</VAR> is not a valid shell variable name, +an attempt is made to turn off readonly status for a readonly variable, +an attempt is made to turn off array status for an array variable, +or an attempt is made to display a non-existent function with <SAMP>`-f'</SAMP>. +</P><P> + +<DT><CODE>echo</CODE> +<DD><A NAME="IDX95"></A> +<TABLE><tr><td> </td><td class=example><pre>echo [-neE] [<VAR>arg</VAR> <small>...</small>] +</pre></td></tr></table>Output the <VAR>arg</VAR>s, separated by spaces, terminated with a +newline. +The return status is always 0. +If <SAMP>`-n'</SAMP> is specified, the trailing newline is suppressed. +If the <SAMP>`-e'</SAMP> option is given, interpretation of the following +backslash-escaped characters is enabled. +The <SAMP>`-E'</SAMP> option disables the interpretation of these escape characters, +even on systems where they are interpreted by default. +The <CODE>xpg_echo</CODE> shell option may be used to +dynamically determine whether or not <CODE>echo</CODE> expands these +escape characters by default. +<CODE>echo</CODE> does not interpret <SAMP>`--'</SAMP> to mean the end of options. +<P> + +<CODE>echo</CODE> interprets the following escape sequences: +<DL COMPACT> +<DT><CODE>\a</CODE> +<DD>alert (bell) +<DT><CODE>\b</CODE> +<DD>backspace +<DT><CODE>\c</CODE> +<DD>suppress further output +<DT><CODE>\e</CODE> +<DD>escape +<DT><CODE>\f</CODE> +<DD>form feed +<DT><CODE>\n</CODE> +<DD>new line +<DT><CODE>\r</CODE> +<DD>carriage return +<DT><CODE>\t</CODE> +<DD>horizontal tab +<DT><CODE>\v</CODE> +<DD>vertical tab +<DT><CODE>\\</CODE> +<DD>backslash +<DT><CODE>\0<VAR>nnn</VAR></CODE> +<DD>the eight-bit character whose value is the octal value <VAR>nnn</VAR> +(zero to three octal digits) +<DT><CODE>\x<VAR>HH</VAR></CODE> +<DD>the eight-bit character whose value is the hexadecimal value <VAR>HH</VAR> +(one or two hex digits) +</DL> +<P> + +<DT><CODE>enable</CODE> +<DD><A NAME="IDX96"></A> +<TABLE><tr><td> </td><td class=example><pre>enable [-a] [-dnps] [-f <VAR>filename</VAR>] [<VAR>name</VAR> <small>...</small>] +</pre></td></tr></table>Enable and disable builtin shell commands. +Disabling a builtin allows a disk command which has the same name +as a shell builtin to be executed without specifying a full pathname, +even though the shell normally searches for builtins before disk commands. +If <SAMP>`-n'</SAMP> is used, the <VAR>name</VAR>s become disabled. Otherwise +<VAR>name</VAR>s are enabled. For example, to use the <CODE>test</CODE> binary +found via <CODE>$PATH</CODE> instead of the shell builtin version, type +<SAMP>`enable -n test'</SAMP>. +<P> + +If the <SAMP>`-p'</SAMP> option is supplied, or no <VAR>name</VAR> arguments appear, +a list of shell builtins is printed. With no other arguments, the list +consists of all enabled shell builtins. +The <SAMP>`-a'</SAMP> option means to list +each builtin with an indication of whether or not it is enabled. +</P><P> + +The <SAMP>`-f'</SAMP> option means to load the new builtin command <VAR>name</VAR> +from shared object <VAR>filename</VAR>, on systems that support dynamic loading. +The <SAMP>`-d'</SAMP> option will delete a builtin loaded with <SAMP>`-f'</SAMP>. +</P><P> + +If there are no options, a list of the shell builtins is displayed. +The <SAMP>`-s'</SAMP> option restricts <CODE>enable</CODE> to the POSIX special +builtins. If <SAMP>`-s'</SAMP> is used with <SAMP>`-f'</SAMP>, the new builtin becomes +a special builtin (see section <A HREF="bashref.html#SEC64">4.4 Special Builtins</A>). +</P><P> + +The return status is zero unless a <VAR>name</VAR> is not a shell builtin +or there is an error loading a new builtin from a shared object. +</P><P> + +<DT><CODE>help</CODE> +<DD><A NAME="IDX97"></A> +<TABLE><tr><td> </td><td class=example><pre>help [-dms] [<VAR>pattern</VAR>] +</pre></td></tr></table>Display helpful information about builtin commands. +If <VAR>pattern</VAR> is specified, <CODE>help</CODE> gives detailed help +on all commands matching <VAR>pattern</VAR>, otherwise a list of +the builtins is printed. +<P> + +Options, if supplied, have the following meanings: +</P><P> + +<DL COMPACT> +<DT><CODE>-d</CODE> +<DD>Display a short description of each <VAR>pattern</VAR> +<DT><CODE>-m</CODE> +<DD>Display the description of each <VAR>pattern</VAR> in a manpage-like format +<DT><CODE>-s</CODE> +<DD>Display only a short usage synopsis for each <VAR>pattern</VAR> +</DL> +<P> + +The return status is zero unless no command matches <VAR>pattern</VAR>. +</P><P> + +<DT><CODE>let</CODE> +<DD><A NAME="IDX98"></A> +<TABLE><tr><td> </td><td class=example><pre>let <VAR>expression</VAR> [<VAR>expression</VAR>] +</pre></td></tr></table>The <CODE>let</CODE> builtin allows arithmetic to be performed on shell +variables. Each <VAR>expression</VAR> is evaluated according to the +rules given below in <A HREF="bashref.html#SEC83">6.5 Shell Arithmetic</A>. If the +last <VAR>expression</VAR> evaluates to 0, <CODE>let</CODE> returns 1; +otherwise 0 is returned. +<P> + +<DT><CODE>local</CODE> +<DD><A NAME="IDX99"></A> +<TABLE><tr><td> </td><td class=example><pre>local [<VAR>option</VAR>] <VAR>name</VAR>[=<VAR>value</VAR>] <small>...</small> +</pre></td></tr></table>For each argument, a local variable named <VAR>name</VAR> is created, +and assigned <VAR>value</VAR>. +The <VAR>option</VAR> can be any of the options accepted by <CODE>declare</CODE>. +<CODE>local</CODE> can only be used within a function; it makes the variable +<VAR>name</VAR> have a visible scope restricted to that function and its +children. The return status is zero unless <CODE>local</CODE> is used outside +a function, an invalid <VAR>name</VAR> is supplied, or <VAR>name</VAR> is a +readonly variable. +<P> + +<DT><CODE>logout</CODE> +<DD><A NAME="IDX100"></A> +<TABLE><tr><td> </td><td class=example><pre>logout [<VAR>n</VAR>] +</pre></td></tr></table>Exit a login shell, returning a status of <VAR>n</VAR> to the shell's +parent. +<P> + +<DT><CODE>mapfile</CODE> +<DD><A NAME="IDX101"></A> +<TABLE><tr><td> </td><td class=example><pre>mapfile [-n <VAR>count</VAR>] [-O <VAR>origin</VAR>] [-s <VAR>count</VAR>] [-t] [-u <VAR>fd</VAR>] [ +-C <VAR>callback</VAR>] [-c <VAR>quantum</VAR>] [<VAR>array</VAR>] +</pre></td></tr></table>Read lines from the standard input into the indexed array variable <VAR>array</VAR>, +or from file descriptor <VAR>fd</VAR> +if the <SAMP>`-u'</SAMP> option is supplied. +The variable <CODE>MAPFILE</CODE> is the default <VAR>array</VAR>. +Options, if supplied, have the following meanings: +<DL COMPACT> + +<DT><CODE>-n</CODE> +<DD>Copy at most <VAR>count</VAR> lines. If <VAR>count</VAR> is 0, all lines are copied. +<DT><CODE>-O</CODE> +<DD>Begin assigning to <VAR>array</VAR> at index <VAR>origin</VAR>. +The default index is 0. +<DT><CODE>-s</CODE> +<DD>Discard the first <VAR>count</VAR> lines read. +<DT><CODE>-t</CODE> +<DD>Remove a trailing newline from each line read. +<DT><CODE>-u</CODE> +<DD>Read lines from file descriptor <VAR>fd</VAR> instead of the standard input. +<DT><CODE>-C</CODE> +<DD>Evaluate <VAR>callback</VAR> each time <VAR>quantum</VAR>P lines are read. +The <SAMP>`-c'</SAMP> option specifies <VAR>quantum</VAR>. +<DT><CODE>-c</CODE> +<DD>Specify the number of lines read between each call to <VAR>callback</VAR>. +</DL> +<P> + +If <SAMP>`-C'</SAMP> is specified without <SAMP>`-c'</SAMP>, +the default quantum is 5000. +When <VAR>callback</VAR> is evaluated, it is supplied the index of the next +array element to be assigned as an additional argument. +<VAR>callback</VAR> is evaluated after the line is read but before the +array element is assigned. +</P><P> + +If not supplied with an explicit origin, <CODE>mapfile</CODE> will clear <VAR>array</VAR> +before assigning to it. +</P><P> + +<CODE>mapfile</CODE> returns successfully unless an invalid option or option +argument is supplied, <VAR>array</VAR> is invalid or unassignable, or <VAR>array</VAR> +is not an indexed array. +</P><P> + +<DT><CODE>printf</CODE> +<DD><A NAME="IDX102"></A> +<TABLE><tr><td> </td><td class=example><pre>printf [-v <VAR>var</VAR>] <VAR>format</VAR> [<VAR>arguments</VAR>] +</pre></td></tr></table>Write the formatted <VAR>arguments</VAR> to the standard output under the +control of the <VAR>format</VAR>. +The <VAR>format</VAR> is a character string which contains three types of objects: +plain characters, which are simply copied to standard output, character +escape sequences, which are converted and copied to the standard output, and +format specifications, each of which causes printing of the next successive +<VAR>argument</VAR>. +In addition to the standard <CODE>printf(1)</CODE> formats, <SAMP>`%b'</SAMP> causes +<CODE>printf</CODE> to expand backslash escape sequences in the corresponding +<VAR>argument</VAR>, +(except that <SAMP>`\c'</SAMP> terminates output, backslashes in +<SAMP>`\''</SAMP>, <SAMP>`\"'</SAMP>, and <SAMP>`\?'</SAMP> are not removed, and octal escapes +beginning with <SAMP>`\0'</SAMP> may contain up to four digits), +and <SAMP>`%q'</SAMP> causes <CODE>printf</CODE> to output the +corresponding <VAR>argument</VAR> in a format that can be reused as shell input. +<P> + +The <SAMP>`-v'</SAMP> option causes the output to be assigned to the variable +<VAR>var</VAR> rather than being printed to the standard output. +</P><P> + +The <VAR>format</VAR> is reused as necessary to consume all of the <VAR>arguments</VAR>. +If the <VAR>format</VAR> requires more <VAR>arguments</VAR> than are supplied, the +extra format specifications behave as if a zero value or null string, as +appropriate, had been supplied. The return value is zero on success, +non-zero on failure. +</P><P> + +<DT><CODE>read</CODE> +<DD><A NAME="IDX103"></A> +<TABLE><tr><td> </td><td class=example><pre>read [-ers] [-a <VAR>aname</VAR>] [-d <VAR>delim</VAR>] [-i <VAR>text</VAR>] [-n <VAR>nchars</VAR>] [-N <VAR>nchars</VAR>] [-p <VAR>prompt</VAR>] [-t <VAR>timeout</VAR>] [-u <VAR>fd</VAR>] [<VAR>name</VAR> <small>...</small>] +</pre></td></tr></table>One line is read from the standard input, or from the file descriptor +<VAR>fd</VAR> supplied as an argument to the <SAMP>`-u'</SAMP> option, and the first word +is assigned to the first <VAR>name</VAR>, the second word to the second <VAR>name</VAR>, +and so on, with leftover words and their intervening separators assigned +to the last <VAR>name</VAR>. +If there are fewer words read from the input stream than names, +the remaining names are assigned empty values. +The characters in the value of the <CODE>IFS</CODE> variable +are used to split the line into words. +The backslash character <SAMP>`\'</SAMP> may be used to remove any special +meaning for the next character read and for line continuation. +If no names are supplied, the line read is assigned to the +variable <CODE>REPLY</CODE>. +The return code is zero, unless end-of-file is encountered, <CODE>read</CODE> +times out (in which case the return code is greater than 128), or an +invalid file descriptor is supplied as the argument to <SAMP>`-u'</SAMP>. +<P> + +Options, if supplied, have the following meanings: +</P><P> + +<DL COMPACT> +<DT><CODE>-a <VAR>aname</VAR></CODE> +<DD>The words are assigned to sequential indices of the array variable +<VAR>aname</VAR>, starting at 0. +All elements are removed from <VAR>aname</VAR> before the assignment. +Other <VAR>name</VAR> arguments are ignored. +<P> + +<DT><CODE>-d <VAR>delim</VAR></CODE> +<DD>The first character of <VAR>delim</VAR> is used to terminate the input line, +rather than newline. +<P> + +<DT><CODE>-e</CODE> +<DD>Readline (see section <A HREF="bashref.html#SEC95">8. Command Line Editing</A>) is used to obtain the line. +Readline uses the current (or default, if line editing was not previously +active) editing settings. +<P> + +<DT><CODE>-i <VAR>text</VAR></CODE> +<DD>If Readline is being used to read the line, <VAR>text</VAR> is placed into +the editing buffer before editing begins. +<P> + +<DT><CODE>-n <VAR>nchars</VAR></CODE> +<DD><CODE>read</CODE> returns after reading <VAR>nchars</VAR> characters rather than +waiting for a complete line of input, but honor a delimiter if fewer +than <VAR>nchars</VAR> characters are read before the delimiter. +<P> + +<DT><CODE>-N <VAR>nchars</VAR></CODE> +<DD><CODE>read</CODE> returns after reading exactly <VAR>nchars</VAR> characters rather +than waiting for a complete line of input, unless EOF is encountered or +<CODE>read</CODE> times out. +Delimiter characters encountered in the input are +not treated specially and do not cause <CODE>read</CODE> to return until +<VAR>nchars</VAR> characters are read. +<P> + +<DT><CODE>-p <VAR>prompt</VAR></CODE> +<DD>Display <VAR>prompt</VAR>, without a trailing newline, before attempting +to read any input. +The prompt is displayed only if input is coming from a terminal. +<P> + +<DT><CODE>-r</CODE> +<DD>If this option is given, backslash does not act as an escape character. +The backslash is considered to be part of the line. +In particular, a backslash-newline pair may not be used as a line +continuation. +<P> + +<DT><CODE>-s</CODE> +<DD>Silent mode. If input is coming from a terminal, characters are +not echoed. +<P> + +<DT><CODE>-t <VAR>timeout</VAR></CODE> +<DD>Cause <CODE>read</CODE> to time out and return failure if a complete line of +input is not read within <VAR>timeout</VAR> seconds. +<VAR>timeout</VAR> may be a decimal number with a fractional portion following +the decimal point. +This option is only effective if <CODE>read</CODE> is reading input from a +terminal, pipe, or other special file; it has no effect when reading +from regular files. +If <VAR>timeout</VAR> is 0, <CODE>read</CODE> returns success if input is available on +the specified file descriptor, failure otherwise. +The exit status is greater than 128 if the timeout is exceeded. +<P> + +<DT><CODE>-u <VAR>fd</VAR></CODE> +<DD>Read input from file descriptor <VAR>fd</VAR>. +<P> + +</DL> +<P> + +<DT><CODE>readarray</CODE> +<DD><A NAME="IDX104"></A> +<TABLE><tr><td> </td><td class=example><pre>readarray [-n <VAR>count</VAR>] [-O <VAR>origin</VAR>] [-s <VAR>count</VAR>] [-t] [-u <VAR>fd</VAR>] [ +-C <VAR>callback</VAR>] [-c <VAR>quantum</VAR>] [<VAR>array</VAR>] +</pre></td></tr></table>Read lines from the standard input into the indexed array variable <VAR>array</VAR>, +or from file descriptor <VAR>fd</VAR> +if the <SAMP>`-u'</SAMP> option is supplied. +<P> + +A synonym for <CODE>mapfile</CODE>. +</P><P> + +<DT><CODE>source</CODE> +<DD><A NAME="IDX105"></A> +<TABLE><tr><td> </td><td class=example><pre>source <VAR>filename</VAR> +</pre></td></tr></table>A synonym for <CODE>.</CODE> (see section <A HREF="bashref.html#SEC59">4.1 Bourne Shell Builtins</A>). +<P> + +<DT><CODE>type</CODE> +<DD><A NAME="IDX106"></A> +<TABLE><tr><td> </td><td class=example><pre>type [-afptP] [<VAR>name</VAR> <small>...</small>] +</pre></td></tr></table>For each <VAR>name</VAR>, indicate how it would be interpreted if used as a +command name. +<P> + +If the <SAMP>`-t'</SAMP> option is used, <CODE>type</CODE> prints a single word +which is one of <SAMP>`alias'</SAMP>, <SAMP>`function'</SAMP>, <SAMP>`builtin'</SAMP>, +<SAMP>`file'</SAMP> or <SAMP>`keyword'</SAMP>, +if <VAR>name</VAR> is an alias, shell function, shell builtin, +disk file, or shell reserved word, respectively. +If the <VAR>name</VAR> is not found, then nothing is printed, and +<CODE>type</CODE> returns a failure status. +</P><P> + +If the <SAMP>`-p'</SAMP> option is used, <CODE>type</CODE> either returns the name +of the disk file that would be executed, or nothing if <SAMP>`-t'</SAMP> +would not return <SAMP>`file'</SAMP>. +</P><P> + +The <SAMP>`-P'</SAMP> option forces a path search for each <VAR>name</VAR>, even if +<SAMP>`-t'</SAMP> would not return <SAMP>`file'</SAMP>. +</P><P> + +If a command is hashed, <SAMP>`-p'</SAMP> and <SAMP>`-P'</SAMP> print the hashed value, +not necessarily the file that appears first in <CODE>$PATH</CODE>. +</P><P> + +If the <SAMP>`-a'</SAMP> option is used, <CODE>type</CODE> returns all of the places +that contain an executable named <VAR>file</VAR>. +This includes aliases and functions, if and only if the <SAMP>`-p'</SAMP> option +is not also used. +</P><P> + +If the <SAMP>`-f'</SAMP> option is used, <CODE>type</CODE> does not attempt to find +shell functions, as with the <CODE>command</CODE> builtin. +</P><P> + +The return status is zero if all of the <VAR>names</VAR> are found, non-zero +if any are not found. +</P><P> + +<DT><CODE>typeset</CODE> +<DD><A NAME="IDX107"></A> +<TABLE><tr><td> </td><td class=example><pre>typeset [-afFrxi] [-p] [<VAR>name</VAR>[=<VAR>value</VAR>] <small>...</small>] +</pre></td></tr></table>The <CODE>typeset</CODE> command is supplied for compatibility with the Korn +shell; however, it has been deprecated in favor of the <CODE>declare</CODE> +builtin command. +<P> + +<DT><CODE>ulimit</CODE> +<DD><A NAME="IDX108"></A> +<TABLE><tr><td> </td><td class=example><pre>ulimit [-abcdefilmnpqrstuvxHST] [<VAR>limit</VAR>] +</pre></td></tr></table><CODE>ulimit</CODE> provides control over the resources available to processes +started by the shell, on systems that allow such control. If an +option is given, it is interpreted as follows: +<DL COMPACT> +<DT><CODE>-S</CODE> +<DD>Change and report the soft limit associated with a resource. +<P> + +<DT><CODE>-H</CODE> +<DD>Change and report the hard limit associated with a resource. +<P> + +<DT><CODE>-a</CODE> +<DD>All current limits are reported. +<P> + +<DT><CODE>-b</CODE> +<DD>The maximum socket buffer size. +<P> + +<DT><CODE>-c</CODE> +<DD>The maximum size of core files created. +<P> + +<DT><CODE>-d</CODE> +<DD>The maximum size of a process's data segment. +<P> + +<DT><CODE>-e</CODE> +<DD>The maximum scheduling priority ("nice"). +<P> + +<DT><CODE>-f</CODE> +<DD>The maximum size of files written by the shell and its children. +<P> + +<DT><CODE>-i</CODE> +<DD>The maximum number of pending signals. +<P> + +<DT><CODE>-l</CODE> +<DD>The maximum size that may be locked into memory. +<P> + +<DT><CODE>-m</CODE> +<DD>The maximum resident set size (many systems do not honor this limit). +<P> + +<DT><CODE>-n</CODE> +<DD>The maximum number of open file descriptors (most systems do not +allow this value to be set). +<P> + +<DT><CODE>-p</CODE> +<DD>The pipe buffer size. +<P> + +<DT><CODE>-q</CODE> +<DD>The maximum number of bytes in POSIX message queues. +<P> + +<DT><CODE>-r</CODE> +<DD>The maximum real-time scheduling priority. +<P> + +<DT><CODE>-s</CODE> +<DD>The maximum stack size. +<P> + +<DT><CODE>-t</CODE> +<DD>The maximum amount of cpu time in seconds. +<P> + +<DT><CODE>-u</CODE> +<DD>The maximum number of processes available to a single user. +<P> + +<DT><CODE>-v</CODE> +<DD>The maximum amount of virtual memory available to the process. +<P> + +<DT><CODE>-x</CODE> +<DD>The maximum number of file locks. +<P> + +<DT><CODE>-T</CODE> +<DD>The maximum number of threads. +<P> + +</DL> +<P> + +If <VAR>limit</VAR> is given, it is the new value of the specified resource; +the special <VAR>limit</VAR> values <CODE>hard</CODE>, <CODE>soft</CODE>, and +<CODE>unlimited</CODE> stand for the current hard limit, the current soft limit, +and no limit, respectively. +A hard limit cannot be increased by a non-root user once it is set; +a soft limit may be increased up to the value of the hard limit. +Otherwise, the current value of the soft limit for the specified resource +is printed, unless the <SAMP>`-H'</SAMP> option is supplied. +When setting new limits, if neither <SAMP>`-H'</SAMP> nor <SAMP>`-S'</SAMP> is supplied, +both the hard and soft limits are set. +If no option is given, then <SAMP>`-f'</SAMP> is assumed. Values are in 1024-byte +increments, except for <SAMP>`-t'</SAMP>, which is in seconds, <SAMP>`-p'</SAMP>, +which is in units of 512-byte blocks, and <SAMP>`-n'</SAMP> and <SAMP>`-u'</SAMP>, which +are unscaled values. +</P><P> + +The return status is zero unless an invalid option or argument is supplied, +or an error occurs while setting a new limit. +</P><P> + +<DT><CODE>unalias</CODE> +<DD><A NAME="IDX109"></A> +<TABLE><tr><td> </td><td class=example><pre>unalias [-a] [<VAR>name</VAR> <small>...</small> ] +</pre></td></tr></table><P> + +Remove each <VAR>name</VAR> from the list of aliases. If <SAMP>`-a'</SAMP> is +supplied, all aliases are removed. +Aliases are described in <A HREF="bashref.html#SEC84">6.6 Aliases</A>. +</P><P> + +</DL> +<P> + +<A NAME="Modifying Shell Behavior"></A> +<HR SIZE="6"> +<A NAME="SEC61"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC60"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC62"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC64"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC58"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC64"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H2> 4.3 Modifying Shell Behavior </H2> +<!--docid::SEC61::--> + +<BLOCKQUOTE><TABLE BORDER=0 CELLSPACING=0> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC62">4.3.1 The Set Builtin</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Change the values of shell attributes and + positional parameters.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC63">4.3.2 The Shopt Builtin</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Modify shell optional behavior.</TD></TR> +</TABLE></BLOCKQUOTE> +<P> + +<A NAME="The Set Builtin"></A> +<HR SIZE="6"> +<A NAME="SEC62"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC61"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC63"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC64"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC61"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC64"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 4.3.1 The Set Builtin </H3> +<!--docid::SEC62::--> +<P> + +This builtin is so complicated that it deserves its own section. <CODE>set</CODE> +allows you to change the values of shell options and set the positional +parameters, or to display the names and values of shell variables. +</P><P> + +<DL COMPACT> +<DT><CODE>set</CODE> +<DD><A NAME="IDX110"></A> +<TABLE><tr><td> </td><td class=example><pre>set [--abefhkmnptuvxBCEHPT] [-o <VAR>option</VAR>] [<VAR>argument</VAR> <small>...</small>] +set [+abefhkmnptuvxBCEHPT] [+o <VAR>option</VAR>] [<VAR>argument</VAR> <small>...</small>] +</pre></td></tr></table><P> + +If no options or arguments are supplied, <CODE>set</CODE> displays the names +and values of all shell variables and functions, sorted according to the +current locale, in a format that may be reused as input +for setting or resetting the currently-set variables. +Read-only variables cannot be reset. +In POSIX mode, only shell variables are listed. +</P><P> + +When options are supplied, they set or unset shell attributes. +Options, if specified, have the following meanings: +</P><P> + +<DL COMPACT> +<DT><CODE>-a</CODE> +<DD>Mark variables and function which are modified or created for export +to the environment of subsequent commands. +<P> + +<DT><CODE>-b</CODE> +<DD>Cause the status of terminated background jobs to be reported +immediately, rather than before printing the next primary prompt. +<P> + +<DT><CODE>-e</CODE> +<DD>Exit immediately if a pipeline (see section <A HREF="bashref.html#SEC17">3.2.2 Pipelines</A>), which may consist +of a single simple command (see section <A HREF="bashref.html#SEC16">3.2.1 Simple Commands</A>), +a subshell command enclosed in parentheses (see section <A HREF="bashref.html#SEC22">3.2.4.3 Grouping Commands</A>), +or one of the commands executed as part of a command list enclosed +by braces (see section <A HREF="bashref.html#SEC22">3.2.4.3 Grouping Commands</A>) +returns a non-zero status. +The shell does not exit if the command that fails is part of the +command list immediately following a <CODE>while</CODE> or <CODE>until</CODE> keyword, +part of the test in an <CODE>if</CODE> statement, +part of any command executed in a <CODE>&&</CODE> or <CODE>||</CODE> list except +the command following the final <CODE>&&</CODE> or <CODE>||</CODE>, +any command in a pipeline but the last, +or if the command's return status is being inverted with <CODE>!</CODE>. +A trap on <CODE>ERR</CODE>, if set, is executed before the shell exits. +<P> + +This option applies to the shell environment and each subshell environment +separately (see section <A HREF="bashref.html#SEC53">3.7.3 Command Execution Environment</A>), and may cause +subshells to exit before executing all the commands in the subshell. +</P><P> + +<DT><CODE>-f</CODE> +<DD>Disable filename expansion (globbing). +<P> + +<DT><CODE>-h</CODE> +<DD>Locate and remember (hash) commands as they are looked up for execution. +This option is enabled by default. +<P> + +<DT><CODE>-k</CODE> +<DD>All arguments in the form of assignment statements are placed +in the environment for a command, not just those that precede +the command name. +<P> + +<DT><CODE>-m</CODE> +<DD>Job control is enabled (see section <A HREF="bashref.html#SEC91">7. Job Control</A>). +<P> + +<DT><CODE>-n</CODE> +<DD>Read commands but do not execute them; this may be used to check a +script for syntax errors. +This option is ignored by interactive shells. +<P> + +<DT><CODE>-o <VAR>option-name</VAR></CODE> +<DD><P> + +Set the option corresponding to <VAR>option-name</VAR>: +</P><P> + +<DL COMPACT> +<DT><CODE>allexport</CODE> +<DD>Same as <CODE>-a</CODE>. +<P> + +<DT><CODE>braceexpand</CODE> +<DD>Same as <CODE>-B</CODE>. +<P> + +<DT><CODE>emacs</CODE> +<DD>Use an <CODE>emacs</CODE>-style line editing interface (see section <A HREF="bashref.html#SEC95">8. Command Line Editing</A>). +This also affects the editing interface used for <CODE>read -e</CODE>. +<P> + +<DT><CODE>errexit</CODE> +<DD>Same as <CODE>-e</CODE>. +<P> + +<DT><CODE>errtrace</CODE> +<DD>Same as <CODE>-E</CODE>. +<P> + +<DT><CODE>functrace</CODE> +<DD>Same as <CODE>-T</CODE>. +<P> + +<DT><CODE>hashall</CODE> +<DD>Same as <CODE>-h</CODE>. +<P> + +<DT><CODE>histexpand</CODE> +<DD>Same as <CODE>-H</CODE>. +<P> + +<DT><CODE>history</CODE> +<DD>Enable command history, as described in <A HREF="bashref.html#SEC120">9.1 Bash History Facilities</A>. +This option is on by default in interactive shells. +<P> + +<DT><CODE>ignoreeof</CODE> +<DD>An interactive shell will not exit upon reading EOF. +<P> + +<DT><CODE>keyword</CODE> +<DD>Same as <CODE>-k</CODE>. +<P> + +<DT><CODE>monitor</CODE> +<DD>Same as <CODE>-m</CODE>. +<P> + +<DT><CODE>noclobber</CODE> +<DD>Same as <CODE>-C</CODE>. +<P> + +<DT><CODE>noexec</CODE> +<DD>Same as <CODE>-n</CODE>. +<P> + +<DT><CODE>noglob</CODE> +<DD>Same as <CODE>-f</CODE>. +<P> + +<DT><CODE>nolog</CODE> +<DD>Currently ignored. +<P> + +<DT><CODE>notify</CODE> +<DD>Same as <CODE>-b</CODE>. +<P> + +<DT><CODE>nounset</CODE> +<DD>Same as <CODE>-u</CODE>. +<P> + +<DT><CODE>onecmd</CODE> +<DD>Same as <CODE>-t</CODE>. +<P> + +<DT><CODE>physical</CODE> +<DD>Same as <CODE>-P</CODE>. +<P> + +<DT><CODE>pipefail</CODE> +<DD>If set, the return value of a pipeline is the value of the last +(rightmost) command to exit with a non-zero status, or zero if all +commands in the pipeline exit successfully. +This option is disabled by default. +<P> + +<DT><CODE>posix</CODE> +<DD>Change the behavior of Bash where the default operation differs +from the POSIX standard to match the standard +(see section <A HREF="bashref.html#SEC90">6.11 Bash POSIX Mode</A>). +This is intended to make Bash behave as a strict superset of that +standard. +<P> + +<DT><CODE>privileged</CODE> +<DD>Same as <CODE>-p</CODE>. +<P> + +<DT><CODE>verbose</CODE> +<DD>Same as <CODE>-v</CODE>. +<P> + +<DT><CODE>vi</CODE> +<DD>Use a <CODE>vi</CODE>-style line editing interface. +This also affects the editing interface used for <CODE>read -e</CODE>. +<P> + +<DT><CODE>xtrace</CODE> +<DD>Same as <CODE>-x</CODE>. +</DL> +<P> + +<DT><CODE>-p</CODE> +<DD>Turn on privileged mode. +In this mode, the <CODE>$BASH_ENV</CODE> and <CODE>$ENV</CODE> files are not +processed, shell functions are not inherited from the environment, +and the <CODE>SHELLOPTS</CODE>, <CODE>BASHOPTS</CODE>, <CODE>CDPATH</CODE> and <CODE>GLOBIGNORE</CODE> +variables, if they appear in the environment, are ignored. +If the shell is started with the effective user (group) id not equal to the +real user (group) id, and the <CODE>-p</CODE> option is not supplied, these actions +are taken and the effective user id is set to the real user id. +If the <CODE>-p</CODE> option is supplied at startup, the effective user id is +not reset. +Turning this option off causes the effective user +and group ids to be set to the real user and group ids. +<P> + +<DT><CODE>-t</CODE> +<DD>Exit after reading and executing one command. +<P> + +<DT><CODE>-u</CODE> +<DD>Treat unset variables and parameters other than the special parameters +<SAMP>`@'</SAMP> or <SAMP>`*'</SAMP> as an error when performing parameter expansion. +An error message will be written to the standard error, and a non-interactive +shell will exit. +<P> + +<DT><CODE>-v</CODE> +<DD>Print shell input lines as they are read. +<P> + +<DT><CODE>-x</CODE> +<DD>Print a trace of simple commands, <CODE>for</CODE> commands, <CODE>case</CODE> +commands, <CODE>select</CODE> commands, and arithmetic <CODE>for</CODE> commands +and their arguments or associated word lists after they are +expanded and before they are executed. The value of the <CODE>PS4</CODE> +variable is expanded and the resultant value is printed before +the command and its expanded arguments. +<P> + +<DT><CODE>-B</CODE> +<DD>The shell will perform brace expansion (see section <A HREF="bashref.html#SEC29">3.5.1 Brace Expansion</A>). +This option is on by default. +<P> + +<DT><CODE>-C</CODE> +<DD>Prevent output redirection using <SAMP>`>'</SAMP>, <SAMP>`>&'</SAMP>, and <SAMP>`<>'</SAMP> +from overwriting existing files. +<P> + +<DT><CODE>-E</CODE> +<DD>If set, any trap on <CODE>ERR</CODE> is inherited by shell functions, command +substitutions, and commands executed in a subshell environment. +The <CODE>ERR</CODE> trap is normally not inherited in such cases. +<P> + +<DT><CODE>-H</CODE> +<DD>Enable <SAMP>`!'</SAMP> style history substitution (see section <A HREF="bashref.html#SEC122">9.3 History Expansion</A>). +This option is on by default for interactive shells. +<P> + +<DT><CODE>-P</CODE> +<DD>If set, do not follow symbolic links when performing commands such as +<CODE>cd</CODE> which change the current directory. The physical directory +is used instead. By default, Bash follows +the logical chain of directories when performing commands +which change the current directory. +<P> + +For example, if <TT>`/usr/sys'</TT> is a symbolic link to <TT>`/usr/local/sys'</TT> +then: +<TABLE><tr><td> </td><td class=example><pre>$ cd /usr/sys; echo $PWD +/usr/sys +$ cd ..; pwd +/usr +</pre></td></tr></table></P><P> + +If <CODE>set -P</CODE> is on, then: +<TABLE><tr><td> </td><td class=example><pre>$ cd /usr/sys; echo $PWD +/usr/local/sys +$ cd ..; pwd +/usr/local +</pre></td></tr></table></P><P> + +<DT><CODE>-T</CODE> +<DD>If set, any trap on <CODE>DEBUG</CODE> and <CODE>RETURN</CODE> are inherited by +shell functions, command substitutions, and commands executed +in a subshell environment. +The <CODE>DEBUG</CODE> and <CODE>RETURN</CODE> traps are normally not inherited +in such cases. +<P> + +<DT><CODE>--</CODE> +<DD>If no arguments follow this option, then the positional parameters are +unset. Otherwise, the positional parameters are set to the +<VAR>arguments</VAR>, even if some of them begin with a <SAMP>`-'</SAMP>. +<P> + +<DT><CODE>-</CODE> +<DD>Signal the end of options, cause all remaining <VAR>arguments</VAR> +to be assigned to the positional parameters. The <SAMP>`-x'</SAMP> +and <SAMP>`-v'</SAMP> options are turned off. +If there are no arguments, the positional parameters remain unchanged. +</DL> +<P> + +Using <SAMP>`+'</SAMP> rather than <SAMP>`-'</SAMP> causes these options to be +turned off. The options can also be used upon invocation of the +shell. The current set of options may be found in <CODE>$-</CODE>. +</P><P> + +The remaining N <VAR>arguments</VAR> are positional parameters and are +assigned, in order, to <CODE>$1</CODE>, <CODE>$2</CODE>, <small>...</small> <CODE>$N</CODE>. +The special parameter <CODE>#</CODE> is set to N. +</P><P> + +The return status is always zero unless an invalid option is supplied. +</DL> +<P> + +<A NAME="The Shopt Builtin"></A> +<HR SIZE="6"> +<A NAME="SEC63"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC62"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC64"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC64"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC61"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC64"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 4.3.2 The Shopt Builtin </H3> +<!--docid::SEC63::--> +<P> + +This builtin allows you to change additional shell optional behavior. +</P><P> + +<DL COMPACT> + +<DT><CODE>shopt</CODE> +<DD><A NAME="IDX111"></A> +<TABLE><tr><td> </td><td class=example><pre>shopt [-pqsu] [-o] [<VAR>optname</VAR> <small>...</small>] +</pre></td></tr></table>Toggle the values of variables controlling optional shell behavior. +With no options, or with the <SAMP>`-p'</SAMP> option, a list of all settable +options is displayed, with an indication of whether or not each is set. +The <SAMP>`-p'</SAMP> option causes output to be displayed in a form that +may be reused as input. +Other options have the following meanings: +<P> + +<DL COMPACT> +<DT><CODE>-s</CODE> +<DD>Enable (set) each <VAR>optname</VAR>. +<P> + +<DT><CODE>-u</CODE> +<DD>Disable (unset) each <VAR>optname</VAR>. +<P> + +<DT><CODE>-q</CODE> +<DD>Suppresses normal output; the return status +indicates whether the <VAR>optname</VAR> is set or unset. +If multiple <VAR>optname</VAR> arguments are given with <SAMP>`-q'</SAMP>, +the return status is zero if all <VAR>optnames</VAR> are enabled; +non-zero otherwise. +<P> + +<DT><CODE>-o</CODE> +<DD>Restricts the values of +<VAR>optname</VAR> to be those defined for the <SAMP>`-o'</SAMP> option to the +<CODE>set</CODE> builtin (see section <A HREF="bashref.html#SEC62">4.3.1 The Set Builtin</A>). +</DL> +<P> + +If either <SAMP>`-s'</SAMP> or <SAMP>`-u'</SAMP> +is used with no <VAR>optname</VAR> arguments, the display is limited to +those options which are set or unset, respectively. +</P><P> + +Unless otherwise noted, the <CODE>shopt</CODE> options are disabled (off) +by default. +</P><P> + +The return status when listing options is zero if all <VAR>optnames</VAR> +are enabled, non-zero otherwise. When setting or unsetting options, +the return status is zero unless an <VAR>optname</VAR> is not a valid shell +option. +</P><P> + +The list of <CODE>shopt</CODE> options is: +<DL COMPACT> + +<DT><CODE>autocd</CODE> +<DD>If set, a command name that is the name of a directory is executed as if +it were the argument to the <CODE>cd</CODE> command. +This option is only used by interactive shells. +<P> + +<DT><CODE>cdable_vars</CODE> +<DD>If this is set, an argument to the <CODE>cd</CODE> builtin command that +is not a directory is assumed to be the name of a variable whose +value is the directory to change to. +<P> + +<DT><CODE>cdspell</CODE> +<DD>If set, minor errors in the spelling of a directory component in a +<CODE>cd</CODE> command will be corrected. +The errors checked for are transposed characters, +a missing character, and a character too many. +If a correction is found, the corrected path is printed, +and the command proceeds. +This option is only used by interactive shells. +<P> + +<DT><CODE>checkhash</CODE> +<DD>If this is set, Bash checks that a command found in the hash +table exists before trying to execute it. If a hashed command no +longer exists, a normal path search is performed. +<P> + +<DT><CODE>checkjobs</CODE> +<DD>If set, Bash lists the status of any stopped and running jobs before +exiting an interactive shell. If any jobs are running, this causes +the exit to be deferred until a second exit is attempted without an +intervening command (see section <A HREF="bashref.html#SEC91">7. Job Control</A>). +The shell always postpones exiting if any jobs are stopped. +<P> + +<DT><CODE>checkwinsize</CODE> +<DD>If set, Bash checks the window size after each command +and, if necessary, updates the values of +<CODE>LINES</CODE> and <CODE>COLUMNS</CODE>. +<P> + +<DT><CODE>cmdhist</CODE> +<DD>If set, Bash +attempts to save all lines of a multiple-line +command in the same history entry. This allows +easy re-editing of multi-line commands. +<P> + +<DT><CODE>compat31</CODE> +<DD>If set, Bash +changes its behavior to that of version 3.1 with respect to quoted +arguments to the conditional command's =~ operator. +<P> + +<DT><CODE>dirspell</CODE> +<DD>If set, Bash +attempts spelling correction on directory names during word completion +if the directory name initially supplied does not exist. +<P> + +<DT><CODE>dotglob</CODE> +<DD>If set, Bash includes filenames beginning with a `.' in +the results of filename expansion. +<P> + +<DT><CODE>execfail</CODE> +<DD>If this is set, a non-interactive shell will not exit if +it cannot execute the file specified as an argument to the <CODE>exec</CODE> +builtin command. An interactive shell does not exit if <CODE>exec</CODE> +fails. +<P> + +<DT><CODE>expand_aliases</CODE> +<DD>If set, aliases are expanded as described below under Aliases, +<A HREF="bashref.html#SEC84">6.6 Aliases</A>. +This option is enabled by default for interactive shells. +<P> + +<DT><CODE>extdebug</CODE> +<DD>If set, behavior intended for use by debuggers is enabled: +<P> + +<OL> +<LI> +The <SAMP>`-F'</SAMP> option to the <CODE>declare</CODE> builtin (see section <A HREF="bashref.html#SEC60">4.2 Bash Builtin Commands</A>) +displays the source file name and line number corresponding to each function +name supplied as an argument. +<P> + +<LI> +If the command run by the <CODE>DEBUG</CODE> trap returns a non-zero value, the +next command is skipped and not executed. +<P> + +<LI> +If the command run by the <CODE>DEBUG</CODE> trap returns a value of 2, and the +shell is executing in a subroutine (a shell function or a shell script +executed by the <CODE>.</CODE> or <CODE>source</CODE> builtins), a call to +<CODE>return</CODE> is simulated. +<P> + +<LI> +<CODE>BASH_ARGC</CODE> and <CODE>BASH_ARGV</CODE> are updated as described in their +descriptions (see section <A HREF="bashref.html#SEC67">5.2 Bash Variables</A>). +<P> + +<LI> +Function tracing is enabled: command substitution, shell functions, and +subshells invoked with <CODE>( <VAR>command</VAR> )</CODE> inherit the +<CODE>DEBUG</CODE> and <CODE>RETURN</CODE> traps. +<P> + +<LI> +Error tracing is enabled: command substitution, shell functions, and +subshells invoked with <CODE>( <VAR>command</VAR> )</CODE> inherit the +<CODE>ERROR</CODE> trap. +</OL> +<P> + +<DT><CODE>extglob</CODE> +<DD>If set, the extended pattern matching features described above +(see section <A HREF="bashref.html#SEC37">3.5.8.1 Pattern Matching</A>) are enabled. +<P> + +<DT><CODE>extquote</CODE> +<DD>If set, <CODE>$'<VAR>string</VAR>'</CODE> and <CODE>$"<VAR>string</VAR>"</CODE> quoting is +performed within <CODE>${<VAR>parameter</VAR>}</CODE> expansions +enclosed in double quotes. This option is enabled by default. +<P> + +<DT><CODE>failglob</CODE> +<DD>If set, patterns which fail to match filenames during filename expansion +result in an expansion error. +<P> + +<DT><CODE>force_fignore</CODE> +<DD>If set, the suffixes specified by the <CODE>FIGNORE</CODE> shell variable +cause words to be ignored when performing word completion even if +the ignored words are the only possible completions. +See section <A HREF="bashref.html#SEC67">5.2 Bash Variables</A>, for a description of <CODE>FIGNORE</CODE>. +This option is enabled by default. +<P> + +<DT><CODE>globstar</CODE> +<DD>If set, the pattern <SAMP>`**'</SAMP> used in a filename expansion context will +match a files and zero or more directories and subdirectories. +If the pattern is followed by a <SAMP>`/'</SAMP>, only directories and +subdirectories match. +<P> + +<DT><CODE>gnu_errfmt</CODE> +<DD>If set, shell error messages are written in the standard GNU error +message format. +<P> + +<DT><CODE>histappend</CODE> +<DD>If set, the history list is appended to the file named by the value +of the <CODE>HISTFILE</CODE> +variable when the shell exits, rather than overwriting the file. +<P> + +<DT><CODE>histreedit</CODE> +<DD>If set, and Readline +is being used, a user is given the opportunity to re-edit a +failed history substitution. +<P> + +<DT><CODE>histverify</CODE> +<DD>If set, and Readline +is being used, the results of history substitution are not immediately +passed to the shell parser. Instead, the resulting line is loaded into +the Readline editing buffer, allowing further modification. +<P> + +<DT><CODE>hostcomplete</CODE> +<DD>If set, and Readline is being used, Bash will attempt to perform +hostname completion when a word containing a <SAMP>`@'</SAMP> is being +completed (see section <A HREF="bashref.html#SEC113">8.4.6 Letting Readline Type For You</A>). This option is enabled +by default. +<P> + +<DT><CODE>huponexit</CODE> +<DD>If set, Bash will send <CODE>SIGHUP</CODE> to all jobs when an interactive +login shell exits (see section <A HREF="bashref.html#SEC56">3.7.6 Signals</A>). +<P> + +<DT><CODE>interactive_comments</CODE> +<DD>Allow a word beginning with <SAMP>`#'</SAMP> +to cause that word and all remaining characters on that +line to be ignored in an interactive shell. +This option is enabled by default. +<P> + +<DT><CODE>lithist</CODE> +<DD>If enabled, and the <CODE>cmdhist</CODE> +option is enabled, multi-line commands are saved to the history with +embedded newlines rather than using semicolon separators where possible. +<P> + +<DT><CODE>login_shell</CODE> +<DD>The shell sets this option if it is started as a login shell +(see section <A HREF="bashref.html#SEC69">6.1 Invoking Bash</A>). +The value may not be changed. +<P> + +<DT><CODE>mailwarn</CODE> +<DD>If set, and a file that Bash is checking for mail has been +accessed since the last time it was checked, the message +<CODE>"The mail in <VAR>mailfile</VAR> has been read"</CODE> is displayed. +<P> + +<DT><CODE>no_empty_cmd_completion</CODE> +<DD>If set, and Readline is being used, Bash will not attempt to search +the <CODE>PATH</CODE> for possible completions when completion is attempted +on an empty line. +<P> + +<DT><CODE>nocaseglob</CODE> +<DD>If set, Bash matches filenames in a case-insensitive fashion when +performing filename expansion. +<P> + +<DT><CODE>nocasematch</CODE> +<DD>If set, Bash matches patterns in a case-insensitive fashion when +performing matching while executing <CODE>case</CODE> or <CODE>[[</CODE> +conditional commands. +<P> + +<DT><CODE>nullglob</CODE> +<DD>If set, Bash allows filename patterns which match no +files to expand to a null string, rather than themselves. +<P> + +<DT><CODE>progcomp</CODE> +<DD>If set, the programmable completion facilities +(see section <A HREF="bashref.html#SEC117">8.6 Programmable Completion</A>) are enabled. +This option is enabled by default. +<P> + +<DT><CODE>promptvars</CODE> +<DD>If set, prompt strings undergo +parameter expansion, command substitution, arithmetic +expansion, and quote removal after being expanded +as described below (see section <A HREF="bashref.html#SEC88">6.9 Controlling the Prompt</A>). +This option is enabled by default. +<P> + +<DT><CODE>restricted_shell</CODE> +<DD>The shell sets this option if it is started in restricted mode +(see section <A HREF="bashref.html#SEC89">6.10 The Restricted Shell</A>). +The value may not be changed. +This is not reset when the startup files are executed, allowing +the startup files to discover whether or not a shell is restricted. +<P> + +<DT><CODE>shift_verbose</CODE> +<DD>If this is set, the <CODE>shift</CODE> +builtin prints an error message when the shift count exceeds the +number of positional parameters. +<P> + +<DT><CODE>sourcepath</CODE> +<DD>If set, the <CODE>source</CODE> builtin uses the value of <CODE>PATH</CODE> +to find the directory containing the file supplied as an argument. +This option is enabled by default. +<P> + +<DT><CODE>xpg_echo</CODE> +<DD>If set, the <CODE>echo</CODE> builtin expands backslash-escape sequences +by default. +<P> + +</DL> +<P> + +The return status when listing options is zero if all <VAR>optnames</VAR> +are enabled, non-zero otherwise. +When setting or unsetting options, the return status is zero unless an +<VAR>optname</VAR> is not a valid shell option. +</P><P> + +</DL> +<P> + +<A NAME="Special Builtins"></A> +<HR SIZE="6"> +<A NAME="SEC64"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC63"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC65"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC58"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC58"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC65"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H2> 4.4 Special Builtins </H2> +<!--docid::SEC64::--> +<P> + +For historical reasons, the POSIX standard has classified +several builtin commands as <EM>special</EM>. +When Bash is executing in POSIX mode, the special builtins +differ from other builtin commands in three respects: +</P><P> + +<OL> +<LI> +Special builtins are found before shell functions during command lookup. +<P> + +<LI> +If a special builtin returns an error status, a non-interactive shell exits. +<P> + +<LI> +Assignment statements preceding the command stay in effect in the shell +environment after the command completes. +</OL> +<P> + +When Bash is not executing in POSIX mode, these builtins behave no +differently than the rest of the Bash builtin commands. +The Bash POSIX mode is described in <A HREF="bashref.html#SEC90">6.11 Bash POSIX Mode</A>. +</P><P> + +These are the POSIX special builtins: +<TABLE><tr><td> </td><td class=example><pre>break : . continue eval exec exit export readonly return set +shift trap unset +</pre></td></tr></table></P><P> + +<A NAME="Shell Variables"></A> +<HR SIZE="6"> +<A NAME="SEC65"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC64"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC66"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC68"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC68"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H1> 5. Shell Variables </H1> +<!--docid::SEC65::--> +<P> + +<BLOCKQUOTE><TABLE BORDER=0 CELLSPACING=0> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC66">5.1 Bourne Shell Variables</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Variables which Bash uses in the same way + as the Bourne Shell.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">List of variables that exist in Bash.</TD></TR> +</TABLE></BLOCKQUOTE> +<P> + +This chapter describes the shell variables that Bash uses. +Bash automatically assigns default values to a number of variables. +</P><P> + +<A NAME="Bourne Shell Variables"></A> +<HR SIZE="6"> +<A NAME="SEC66"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC65"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC67"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC65"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC65"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC68"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H2> 5.1 Bourne Shell Variables </H2> +<!--docid::SEC66::--> +<P> + +Bash uses certain shell variables in the same way as the Bourne shell. +In some cases, Bash assigns a default value to the variable. +</P><P> + +<DL COMPACT> + +<A NAME="IDX112"></A> +<DT><CODE>CDPATH</CODE> +<DD><A NAME="IDX113"></A> +A colon-separated list of directories used as a search path for +the <CODE>cd</CODE> builtin command. +<P> + +<A NAME="IDX114"></A> +<DT><CODE>HOME</CODE> +<DD><A NAME="IDX115"></A> +The current user's home directory; the default for the <CODE>cd</CODE> builtin +command. +The value of this variable is also used by tilde expansion +(see section <A HREF="bashref.html#SEC30">3.5.2 Tilde Expansion</A>). +<P> + +<A NAME="IDX116"></A> +<DT><CODE>IFS</CODE> +<DD><A NAME="IDX117"></A> +A list of characters that separate fields; used when the shell splits +words as part of expansion. +<P> + +<A NAME="IDX118"></A> +<DT><CODE>MAIL</CODE> +<DD><A NAME="IDX119"></A> +If this parameter is set to a filename and the <CODE>MAILPATH</CODE> variable +is not set, Bash informs the user of the arrival of mail in +the specified file. +<P> + +<A NAME="IDX120"></A> +<DT><CODE>MAILPATH</CODE> +<DD><A NAME="IDX121"></A> +A colon-separated list of filenames which the shell periodically checks +for new mail. +Each list entry can specify the message that is printed when new mail +arrives in the mail file by separating the file name from the message with +a <SAMP>`?'</SAMP>. +When used in the text of the message, <CODE>$_</CODE> expands to the name of +the current mail file. +<P> + +<A NAME="IDX122"></A> +<DT><CODE>OPTARG</CODE> +<DD><A NAME="IDX123"></A> +The value of the last option argument processed by the <CODE>getopts</CODE> builtin. +<P> + +<A NAME="IDX124"></A> +<DT><CODE>OPTIND</CODE> +<DD><A NAME="IDX125"></A> +The index of the last option argument processed by the <CODE>getopts</CODE> builtin. +<P> + +<A NAME="IDX126"></A> +<DT><CODE>PATH</CODE> +<DD><A NAME="IDX127"></A> +A colon-separated list of directories in which the shell looks for +commands. +A zero-length (null) directory name in the value of <CODE>PATH</CODE> indicates the +current directory. +A null directory name may appear as two adjacent colons, or as an initial +or trailing colon. +<P> + +<A NAME="IDX128"></A> +<DT><CODE>PS1</CODE> +<DD><A NAME="IDX129"></A> +The primary prompt string. The default value is <SAMP>`\s-\v\$ '</SAMP>. +See section <A HREF="bashref.html#SEC88">6.9 Controlling the Prompt</A>, for the complete list of escape +sequences that are expanded before <CODE>PS1</CODE> is displayed. +<P> + +<A NAME="IDX130"></A> +<DT><CODE>PS2</CODE> +<DD><A NAME="IDX131"></A> +The secondary prompt string. The default value is <SAMP>`> '</SAMP>. +<P> + +</DL> +<P> + +<A NAME="Bash Variables"></A> +<HR SIZE="6"> +<A NAME="SEC67"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC66"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC68"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC65"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC65"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC68"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H2> 5.2 Bash Variables </H2> +<!--docid::SEC67::--> +<P> + +These variables are set or used by Bash, but other shells +do not normally treat them specially. +</P><P> + +A few variables used by Bash are described in different chapters: +variables for controlling the job control facilities +(see section <A HREF="bashref.html#SEC94">7.3 Job Control Variables</A>). +</P><P> + +<DL COMPACT> + +<A NAME="IDX132"></A> +<DT><CODE>BASH</CODE> +<DD><A NAME="IDX133"></A> +The full pathname used to execute the current instance of Bash. +<P> + +<A NAME="IDX134"></A> +<DT><CODE>BASHOPTS</CODE> +<DD><A NAME="IDX135"></A> +A colon-separated list of enabled shell options. Each word in +the list is a valid argument for the <SAMP>`-s'</SAMP> option to the +<CODE>shopt</CODE> builtin command (see section <A HREF="bashref.html#SEC63">4.3.2 The Shopt Builtin</A>). +The options appearing in <CODE>BASHOPTS</CODE> are those reported +as <SAMP>`on'</SAMP> by <SAMP>`shopt'</SAMP>. +If this variable is in the environment when Bash +starts up, each shell option in the list will be enabled before +reading any startup files. This variable is readonly. +<P> + +<A NAME="IDX136"></A> +<DT><CODE>BASHPID</CODE> +<DD><A NAME="IDX137"></A> +Expands to the process id of the current Bash process. +This differs from <CODE>$$</CODE> under certain circumstances, such as subshells +that do not require Bash to be re-initialized. +<P> + +<A NAME="IDX138"></A> +<DT><CODE>BASH_ALIASES</CODE> +<DD><A NAME="IDX139"></A> +An associative array variable whose members correspond to the internal +list of aliases as maintained by the <CODE>alias</CODE> builtin +(see section <A HREF="bashref.html#SEC59">4.1 Bourne Shell Builtins</A>). +Elements added to this array appear in the alias list; unsetting array +elements cause aliases to be removed from the alias list. +<P> + +<A NAME="IDX140"></A> +<DT><CODE>BASH_ARGC</CODE> +<DD><A NAME="IDX141"></A> +An array variable whose values are the number of parameters in each +frame of the current bash execution call stack. The number of +parameters to the current subroutine (shell function or script executed +with <CODE>.</CODE> or <CODE>source</CODE>) is at the top of the stack. When a +subroutine is executed, the number of parameters passed is pushed onto +<CODE>BASH_ARGC</CODE>. +The shell sets <CODE>BASH_ARGC</CODE> only when in extended debugging mode +(see <A HREF="bashref.html#SEC63">4.3.2 The Shopt Builtin</A> +for a description of the <CODE>extdebug</CODE> option to the <CODE>shopt</CODE> +builtin). +<P> + +<A NAME="IDX142"></A> +<DT><CODE>BASH_ARGV</CODE> +<DD><A NAME="IDX143"></A> +An array variable containing all of the parameters in the current bash +execution call stack. The final parameter of the last subroutine call +is at the top of the stack; the first parameter of the initial call is +at the bottom. When a subroutine is executed, the parameters supplied +are pushed onto <CODE>BASH_ARGV</CODE>. +The shell sets <CODE>BASH_ARGV</CODE> only when in extended debugging mode +(see <A HREF="bashref.html#SEC63">4.3.2 The Shopt Builtin</A> +for a description of the <CODE>extdebug</CODE> option to the <CODE>shopt</CODE> +builtin). +<P> + +<A NAME="IDX144"></A> +<DT><CODE>BASH_CMDS</CODE> +<DD><A NAME="IDX145"></A> +An associative array variable whose members correspond to the internal +hash table of commands as maintained by the <CODE>hash</CODE> builtin +(see section <A HREF="bashref.html#SEC59">4.1 Bourne Shell Builtins</A>). +Elements added to this array appear in the hash table; unsetting array +elements cause commands to be removed from the hash table. +<P> + +<A NAME="IDX146"></A> +<DT><CODE>BASH_COMMAND</CODE> +<DD><A NAME="IDX147"></A> +The command currently being executed or about to be executed, unless the +shell is executing a command as the result of a trap, +in which case it is the command executing at the time of the trap. +<P> + +<A NAME="IDX148"></A> +<DT><CODE>BASH_ENV</CODE> +<DD><A NAME="IDX149"></A> +If this variable is set when Bash is invoked to execute a shell +script, its value is expanded and used as the name of a startup file +to read before executing the script. See section <A HREF="bashref.html#SEC70">6.2 Bash Startup Files</A>. +<P> + +<A NAME="IDX150"></A> +<DT><CODE>BASH_EXECUTION_STRING</CODE> +<DD><A NAME="IDX151"></A> +The command argument to the <SAMP>`-c'</SAMP> invocation option. +<P> + +<A NAME="IDX152"></A> +<DT><CODE>BASH_LINENO</CODE> +<DD><A NAME="IDX153"></A> +An array variable whose members are the line numbers in source files +corresponding to each member of <VAR>FUNCNAME</VAR>. +<CODE>${BASH_LINENO[$i]}</CODE> is the line number in the source file where +<CODE>${FUNCNAME[$i]}</CODE> was called (or <CODE>${BASH_LINENO[$i-1]}</CODE> if +referenced within another shell function). +The corresponding source file name is <CODE>${BASH_SOURCE[$i]}</CODE>. +Use <CODE>LINENO</CODE> to obtain the current line number. +<P> + +<A NAME="IDX154"></A> +<DT><CODE>BASH_REMATCH</CODE> +<DD><A NAME="IDX155"></A> +An array variable whose members are assigned by the <SAMP>`=~'</SAMP> binary +operator to the <CODE>[[</CODE> conditional command +(see section <A HREF="bashref.html#SEC21">3.2.4.2 Conditional Constructs</A>). +The element with index 0 is the portion of the string +matching the entire regular expression. +The element with index <VAR>n</VAR> is the portion of the +string matching the <VAR>n</VAR>th parenthesized subexpression. +This variable is read-only. +<P> + +<A NAME="IDX156"></A> +<DT><CODE>BASH_SOURCE</CODE> +<DD><A NAME="IDX157"></A> +An array variable whose members are the source filenames corresponding +to the elements in the <CODE>FUNCNAME</CODE> array variable. +<P> + +<A NAME="IDX158"></A> +<DT><CODE>BASH_SUBSHELL</CODE> +<DD><A NAME="IDX159"></A> +Incremented by one each time a subshell or subshell environment is spawned. +The initial value is 0. +<P> + +<A NAME="IDX160"></A> +<DT><CODE>BASH_VERSINFO</CODE> +<DD><A NAME="IDX161"></A> +A readonly array variable (see section <A HREF="bashref.html#SEC85">6.7 Arrays</A>) +whose members hold version information for this instance of Bash. +The values assigned to the array members are as follows: +<P> + +<DL COMPACT> + +<DT><CODE>BASH_VERSINFO[0]</CODE> +<DD>The major version number (the <VAR>release</VAR>). +<P> + +<DT><CODE>BASH_VERSINFO[1]</CODE> +<DD>The minor version number (the <VAR>version</VAR>). +<P> + +<DT><CODE>BASH_VERSINFO[2]</CODE> +<DD>The patch level. +<P> + +<DT><CODE>BASH_VERSINFO[3]</CODE> +<DD>The build version. +<P> + +<DT><CODE>BASH_VERSINFO[4]</CODE> +<DD>The release status (e.g., <VAR>beta1</VAR>). +<P> + +<DT><CODE>BASH_VERSINFO[5]</CODE> +<DD>The value of <CODE>MACHTYPE</CODE>. +<P> + +</DL> +<P> + +<A NAME="IDX162"></A> +<DT><CODE>BASH_VERSION</CODE> +<DD><A NAME="IDX163"></A> +The version number of the current instance of Bash. +<P> + +<A NAME="IDX164"></A> +<DT><CODE>BASH_XTRACEFD</CODE> +<DD><A NAME="IDX165"></A> +If set to an integer corresponding to a valid file descriptor, Bash +will write the trace output generated when <SAMP>`set -x'</SAMP> +is enabled to that file descriptor. +This allows tracing output to be separated from diagnostic and error +messages. +The file descriptor is closed when <CODE>BASH_XTRACEFD</CODE> is unset or assigned +a new value. +Unsetting <CODE>BASH_XTRACEFD</CODE> or assigning it the empty string causes the +trace output to be sent to the standard error. +Note that setting <CODE>BASH_XTRACEFD</CODE> to 2 (the standard error file +descriptor) and then unsetting it will result in the standard error +being closed. +<P> + +<A NAME="IDX166"></A> +<DT><CODE>COLUMNS</CODE> +<DD><A NAME="IDX167"></A> +Used by the <CODE>select</CODE> builtin command to determine the terminal width +when printing selection lists. Automatically set upon receipt of a +<CODE>SIGWINCH</CODE>. +<P> + +<A NAME="IDX168"></A> +<DT><CODE>COMP_CWORD</CODE> +<DD><A NAME="IDX169"></A> +An index into <CODE>${COMP_WORDS}</CODE> of the word containing the current +cursor position. +This variable is available only in shell functions invoked by the +programmable completion facilities (see section <A HREF="bashref.html#SEC117">8.6 Programmable Completion</A>). +<P> + +<A NAME="IDX170"></A> +<DT><CODE>COMP_LINE</CODE> +<DD><A NAME="IDX171"></A> +The current command line. +This variable is available only in shell functions and external +commands invoked by the +programmable completion facilities (see section <A HREF="bashref.html#SEC117">8.6 Programmable Completion</A>). +<P> + +<A NAME="IDX172"></A> +<DT><CODE>COMP_POINT</CODE> +<DD><A NAME="IDX173"></A> +The index of the current cursor position relative to the beginning of +the current command. +If the current cursor position is at the end of the current command, +the value of this variable is equal to <CODE>${#COMP_LINE}</CODE>. +This variable is available only in shell functions and external +commands invoked by the +programmable completion facilities (see section <A HREF="bashref.html#SEC117">8.6 Programmable Completion</A>). +<P> + +<A NAME="IDX174"></A> +<DT><CODE>COMP_TYPE</CODE> +<DD><A NAME="IDX175"></A> +Set to an integer value corresponding to the type of completion attempted +that caused a completion function to be called: +<VAR>TAB</VAR>, for normal completion, +<SAMP>`?'</SAMP>, for listing completions after successive tabs, +<SAMP>`!'</SAMP>, for listing alternatives on partial word completion, +<SAMP>`@'</SAMP>, to list completions if the word is not unmodified, +or +<SAMP>`%'</SAMP>, for menu completion. +This variable is available only in shell functions and external +commands invoked by the +programmable completion facilities (see section <A HREF="bashref.html#SEC117">8.6 Programmable Completion</A>). +<P> + +<A NAME="IDX176"></A> +<DT><CODE>COMP_KEY</CODE> +<DD><A NAME="IDX177"></A> +The key (or final key of a key sequence) used to invoke the current +completion function. +<P> + +<A NAME="IDX178"></A> +<DT><CODE>COMP_WORDBREAKS</CODE> +<DD><A NAME="IDX179"></A> +The set of characters that the Readline library treats as word +separators when performing word completion. +If <CODE>COMP_WORDBREAKS</CODE> is unset, it loses its special properties, +even if it is subsequently reset. +<P> + +<A NAME="IDX180"></A> +<DT><CODE>COMP_WORDS</CODE> +<DD><A NAME="IDX181"></A> +An array variable consisting of the individual +words in the current command line. +The line is split into words as Readline would split it, using +<CODE>COMP_WORDBREAKS</CODE> as described above. +This variable is available only in shell functions invoked by the +programmable completion facilities (see section <A HREF="bashref.html#SEC117">8.6 Programmable Completion</A>). +<P> + +<A NAME="IDX182"></A> +<DT><CODE>COMPREPLY</CODE> +<DD><A NAME="IDX183"></A> +An array variable from which Bash reads the possible completions +generated by a shell function invoked by the programmable completion +facility (see section <A HREF="bashref.html#SEC117">8.6 Programmable Completion</A>). +<P> + +<A NAME="IDX184"></A> +<DT><CODE>DIRSTACK</CODE> +<DD><A NAME="IDX185"></A> +An array variable containing the current contents of the directory stack. +Directories appear in the stack in the order they are displayed by the +<CODE>dirs</CODE> builtin. +Assigning to members of this array variable may be used to modify +directories already in the stack, but the <CODE>pushd</CODE> and <CODE>popd</CODE> +builtins must be used to add and remove directories. +Assignment to this variable will not change the current directory. +If <CODE>DIRSTACK</CODE> is unset, it loses its special properties, even if +it is subsequently reset. +<P> + +<A NAME="IDX186"></A> +<DT><CODE>EMACS</CODE> +<DD><A NAME="IDX187"></A> +If Bash finds this variable in the environment when the shell +starts with value <SAMP>`t'</SAMP>, it assumes that the shell is running in an +emacs shell buffer and disables line editing. +<P> + +<A NAME="IDX188"></A> +<DT><CODE>EUID</CODE> +<DD><A NAME="IDX189"></A> +The numeric effective user id of the current user. This variable +is readonly. +<P> + +<A NAME="IDX190"></A> +<DT><CODE>FCEDIT</CODE> +<DD><A NAME="IDX191"></A> +The editor used as a default by the <SAMP>`-e'</SAMP> option to the <CODE>fc</CODE> +builtin command. +<P> + +<A NAME="IDX192"></A> +<DT><CODE>FIGNORE</CODE> +<DD><A NAME="IDX193"></A> +A colon-separated list of suffixes to ignore when performing +filename completion. +A file name whose suffix matches one of the entries in +<CODE>FIGNORE</CODE> +is excluded from the list of matched file names. A sample +value is <SAMP>`.o:~'</SAMP> +<P> + +<A NAME="IDX194"></A> +<DT><CODE>FUNCNAME</CODE> +<DD><A NAME="IDX195"></A> +An array variable containing the names of all shell functions +currently in the execution call stack. +The element with index 0 is the name of any currently-executing +shell function. +The bottom-most element is <CODE>"main"</CODE>. +This variable exists only when a shell function is executing. +Assignments to <CODE>FUNCNAME</CODE> have no effect and return an error status. +If <CODE>FUNCNAME</CODE> is unset, it loses its special properties, even if +it is subsequently reset. +<P> + +<A NAME="IDX196"></A> +<DT><CODE>GLOBIGNORE</CODE> +<DD><A NAME="IDX197"></A> +A colon-separated list of patterns defining the set of filenames to +be ignored by filename expansion. +If a filename matched by a filename expansion pattern also matches one +of the patterns in <CODE>GLOBIGNORE</CODE>, it is removed from the list +of matches. +<P> + +<A NAME="IDX198"></A> +<DT><CODE>GROUPS</CODE> +<DD><A NAME="IDX199"></A> +An array variable containing the list of groups of which the current +user is a member. +Assignments to <CODE>GROUPS</CODE> have no effect and return an error status. +If <CODE>GROUPS</CODE> is unset, it loses its special properties, even if it is +subsequently reset. +<P> + +<A NAME="IDX200"></A> +<DT><CODE>histchars</CODE> +<DD><A NAME="IDX201"></A> +Up to three characters which control history expansion, quick +substitution, and tokenization (see section <A HREF="bashref.html#SEC122">9.3 History Expansion</A>). +The first character is the +<VAR>history expansion</VAR> character, that is, the character which signifies the +start of a history expansion, normally <SAMP>`!'</SAMP>. The second character is the +character which signifies `quick substitution' when seen as the first +character on a line, normally <SAMP>`^'</SAMP>. The optional third character is the +character which indicates that the remainder of the line is a comment when +found as the first character of a word, usually <SAMP>`#'</SAMP>. The history +comment character causes history substitution to be skipped for the +remaining words on the line. It does not necessarily cause the shell +parser to treat the rest of the line as a comment. +<P> + +<A NAME="IDX202"></A> +<DT><CODE>HISTCMD</CODE> +<DD><A NAME="IDX203"></A> +The history number, or index in the history list, of the current +command. If <CODE>HISTCMD</CODE> is unset, it loses its special properties, +even if it is subsequently reset. +<P> + +<A NAME="IDX204"></A> +<DT><CODE>HISTCONTROL</CODE> +<DD><A NAME="IDX205"></A> +A colon-separated list of values controlling how commands are saved on +the history list. +If the list of values includes <SAMP>`ignorespace'</SAMP>, lines which begin +with a space character are not saved in the history list. +A value of <SAMP>`ignoredups'</SAMP> causes lines which match the previous +history entry to not be saved. +A value of <SAMP>`ignoreboth'</SAMP> is shorthand for +<SAMP>`ignorespace'</SAMP> and <SAMP>`ignoredups'</SAMP>. +A value of <SAMP>`erasedups'</SAMP> causes all previous lines matching the +current line to be removed from the history list before that line +is saved. +Any value not in the above list is ignored. +If <CODE>HISTCONTROL</CODE> is unset, or does not include a valid value, +all lines read by the shell parser are saved on the history list, +subject to the value of <CODE>HISTIGNORE</CODE>. +The second and subsequent lines of a multi-line compound command are +not tested, and are added to the history regardless of the value of +<CODE>HISTCONTROL</CODE>. +<P> + +<A NAME="IDX206"></A> +<DT><CODE>HISTFILE</CODE> +<DD><A NAME="IDX207"></A> +The name of the file to which the command history is saved. The +default value is <TT>`~/.bash_history'</TT>. +<P> + +<A NAME="IDX208"></A> +<DT><CODE>HISTFILESIZE</CODE> +<DD><A NAME="IDX209"></A> +The maximum number of lines contained in the history file. When this +variable is assigned a value, the history file is truncated, if +necessary, by removing the oldest entries, +to contain no more than that number of lines. +The history file is also truncated to this size after +writing it when an interactive shell exits. +The default value is 500. +<P> + +<A NAME="IDX210"></A> +<DT><CODE>HISTIGNORE</CODE> +<DD><A NAME="IDX211"></A> +A colon-separated list of patterns used to decide which command +lines should be saved on the history list. Each pattern is +anchored at the beginning of the line and must match the complete +line (no implicit <SAMP>`*'</SAMP> is appended). Each pattern is tested +against the line after the checks specified by <CODE>HISTCONTROL</CODE> +are applied. In addition to the normal shell pattern matching +characters, <SAMP>`&'</SAMP> matches the previous history line. <SAMP>`&'</SAMP> +may be escaped using a backslash; the backslash is removed +before attempting a match. +The second and subsequent lines of a multi-line compound command are +not tested, and are added to the history regardless of the value of +<CODE>HISTIGNORE</CODE>. +<P> + +<CODE>HISTIGNORE</CODE> subsumes the function of <CODE>HISTCONTROL</CODE>. A +pattern of <SAMP>`&'</SAMP> is identical to <CODE>ignoredups</CODE>, and a +pattern of <SAMP>`[ ]*'</SAMP> is identical to <CODE>ignorespace</CODE>. +Combining these two patterns, separating them with a colon, +provides the functionality of <CODE>ignoreboth</CODE>. +</P><P> + +<A NAME="IDX212"></A> +<DT><CODE>HISTSIZE</CODE> +<DD><A NAME="IDX213"></A> +The maximum number of commands to remember on the history list. +The default value is 500. +<P> + +<A NAME="IDX214"></A> +<DT><CODE>HISTTIMEFORMAT</CODE> +<DD><A NAME="IDX215"></A> +If this variable is set and not null, its value is used as a format string +for <VAR>strftime</VAR> to print the time stamp associated with each history +entry displayed by the <CODE>history</CODE> builtin. +If this variable is set, time stamps are written to the history file so +they may be preserved across shell sessions. +This uses the history comment character to distinguish timestamps from +other history lines. +<P> + +<A NAME="IDX216"></A> +<DT><CODE>HOSTFILE</CODE> +<DD><A NAME="IDX217"></A> +Contains the name of a file in the same format as <TT>`/etc/hosts'</TT> that +should be read when the shell needs to complete a hostname. +The list of possible hostname completions may be changed while the shell +is running; +the next time hostname completion is attempted after the +value is changed, Bash adds the contents of the new file to the +existing list. +If <CODE>HOSTFILE</CODE> is set, but has no value, or does not name a readable file, +Bash attempts to read +<TT>`/etc/hosts'</TT> to obtain the list of possible hostname completions. +When <CODE>HOSTFILE</CODE> is unset, the hostname list is cleared. +<P> + +<A NAME="IDX218"></A> +<DT><CODE>HOSTNAME</CODE> +<DD><A NAME="IDX219"></A> +The name of the current host. +<P> + +<A NAME="IDX220"></A> +<DT><CODE>HOSTTYPE</CODE> +<DD><A NAME="IDX221"></A> +A string describing the machine Bash is running on. +<P> + +<A NAME="IDX222"></A> +<DT><CODE>IGNOREEOF</CODE> +<DD><A NAME="IDX223"></A> +Controls the action of the shell on receipt of an <CODE>EOF</CODE> character +as the sole input. If set, the value denotes the number +of consecutive <CODE>EOF</CODE> characters that can be read as the +first character on an input line +before the shell will exit. If the variable exists but does not +have a numeric value (or has no value) then the default is 10. +If the variable does not exist, then <CODE>EOF</CODE> signifies the end of +input to the shell. This is only in effect for interactive shells. +<P> + +<A NAME="IDX224"></A> +<DT><CODE>INPUTRC</CODE> +<DD><A NAME="IDX225"></A> +The name of the Readline initialization file, overriding the default +of <TT>`~/.inputrc'</TT>. +<P> + +<A NAME="IDX226"></A> +<DT><CODE>LANG</CODE> +<DD><A NAME="IDX227"></A> +Used to determine the locale category for any category not specifically +selected with a variable starting with <CODE>LC_</CODE>. +<P> + +<A NAME="IDX228"></A> +<DT><CODE>LC_ALL</CODE> +<DD><A NAME="IDX229"></A> +This variable overrides the value of <CODE>LANG</CODE> and any other +<CODE>LC_</CODE> variable specifying a locale category. +<P> + +<A NAME="IDX230"></A> +<DT><CODE>LC_COLLATE</CODE> +<DD><A NAME="IDX231"></A> +This variable determines the collation order used when sorting the +results of filename expansion, and +determines the behavior of range expressions, equivalence classes, +and collating sequences within filename expansion and pattern matching +(see section <A HREF="bashref.html#SEC36">3.5.8 Filename Expansion</A>). +<P> + +<A NAME="IDX232"></A> +<DT><CODE>LC_CTYPE</CODE> +<DD><A NAME="IDX233"></A> +This variable determines the interpretation of characters and the +behavior of character classes within filename expansion and pattern +matching (see section <A HREF="bashref.html#SEC36">3.5.8 Filename Expansion</A>). +<P> + +<A NAME="IDX234"></A> +<DT><CODE>LC_MESSAGES</CODE> +<DD><A NAME="IDX235"></A> +This variable determines the locale used to translate double-quoted +strings preceded by a <SAMP>`$'</SAMP> (see section <A HREF="bashref.html#SEC13">3.1.2.5 Locale-Specific Translation</A>). +<P> + +<A NAME="IDX236"></A> +<DT><CODE>LC_NUMERIC</CODE> +<DD><A NAME="IDX237"></A> +This variable determines the locale category used for number formatting. +<P> + +<A NAME="IDX238"></A> +<DT><CODE>LINENO</CODE> +<DD><A NAME="IDX239"></A> +The line number in the script or shell function currently executing. +<P> + +<A NAME="IDX240"></A> +<DT><CODE>LINES</CODE> +<DD><A NAME="IDX241"></A> +Used by the <CODE>select</CODE> builtin command to determine the column length +for printing selection lists. Automatically set upon receipt of a +<CODE>SIGWINCH</CODE>. +<P> + +<A NAME="IDX242"></A> +<DT><CODE>MACHTYPE</CODE> +<DD><A NAME="IDX243"></A> +A string that fully describes the system type on which Bash +is executing, in the standard GNU <VAR>cpu-company-system</VAR> format. +<P> + +<A NAME="IDX244"></A> +<DT><CODE>MAILCHECK</CODE> +<DD><A NAME="IDX245"></A> +How often (in seconds) that the shell should check for mail in the +files specified in the <CODE>MAILPATH</CODE> or <CODE>MAIL</CODE> variables. +The default is 60 seconds. When it is time to check +for mail, the shell does so before displaying the primary prompt. +If this variable is unset, or set to a value that is not a number +greater than or equal to zero, the shell disables mail checking. +<P> + +<A NAME="IDX246"></A> +<DT><CODE>OLDPWD</CODE> +<DD><A NAME="IDX247"></A> +The previous working directory as set by the <CODE>cd</CODE> builtin. +<P> + +<A NAME="IDX248"></A> +<DT><CODE>OPTERR</CODE> +<DD><A NAME="IDX249"></A> +If set to the value 1, Bash displays error messages +generated by the <CODE>getopts</CODE> builtin command. +<P> + +<A NAME="IDX250"></A> +<DT><CODE>OSTYPE</CODE> +<DD><A NAME="IDX251"></A> +A string describing the operating system Bash is running on. +<P> + +<A NAME="IDX252"></A> +<DT><CODE>PIPESTATUS</CODE> +<DD><A NAME="IDX253"></A> +An array variable (see section <A HREF="bashref.html#SEC85">6.7 Arrays</A>) +containing a list of exit status values from the processes +in the most-recently-executed foreground pipeline (which may +contain only a single command). +<P> + +<A NAME="IDX254"></A> +<DT><CODE>POSIXLY_CORRECT</CODE> +<DD><A NAME="IDX255"></A> +If this variable is in the environment when <CODE>bash</CODE> starts, the shell +enters POSIX mode (see section <A HREF="bashref.html#SEC90">6.11 Bash POSIX Mode</A>) before reading the +startup files, as if the <SAMP>`--posix'</SAMP> invocation option had been supplied. +If it is set while the shell is running, <CODE>bash</CODE> enables POSIX mode, +as if the command +<TABLE><tr><td> </td><td class=example><pre><CODE>set -o posix</CODE> +</pre></td></tr></table>had been executed. +<P> + +<A NAME="IDX256"></A> +<DT><CODE>PPID</CODE> +<DD><A NAME="IDX257"></A> +The process ID of the shell's parent process. This variable +is readonly. +<P> + +<A NAME="IDX258"></A> +<DT><CODE>PROMPT_COMMAND</CODE> +<DD><A NAME="IDX259"></A> +If set, the value is interpreted as a command to execute +before the printing of each primary prompt (<CODE>$PS1</CODE>). +<P> + +<A NAME="IDX260"></A> +<DT><CODE>PROMPT_DIRTRIM</CODE> +<DD><A NAME="IDX261"></A> +If set to a number greater than zero, the value is used as the number of +trailing directory components to retain when expanding the <CODE>\w</CODE> and +<CODE>\W</CODE> prompt string escapes (see section <A HREF="bashref.html#SEC88">6.9 Controlling the Prompt</A>). +Characters removed are replaced with an ellipsis. +<P> + +<A NAME="IDX262"></A> +<DT><CODE>PS3</CODE> +<DD><A NAME="IDX263"></A> +The value of this variable is used as the prompt for the +<CODE>select</CODE> command. If this variable is not set, the +<CODE>select</CODE> command prompts with <SAMP>`#? '</SAMP> +<P> + +<A NAME="IDX264"></A> +<DT><CODE>PS4</CODE> +<DD><A NAME="IDX265"></A> +The value is the prompt printed before the command line is echoed +when the <SAMP>`-x'</SAMP> option is set (see section <A HREF="bashref.html#SEC62">4.3.1 The Set Builtin</A>). +The first character of <CODE>PS4</CODE> is replicated multiple times, as +necessary, to indicate multiple levels of indirection. +The default is <SAMP>`+ '</SAMP>. +<P> + +<A NAME="IDX266"></A> +<DT><CODE>PWD</CODE> +<DD><A NAME="IDX267"></A> +The current working directory as set by the <CODE>cd</CODE> builtin. +<P> + +<A NAME="IDX268"></A> +<DT><CODE>RANDOM</CODE> +<DD><A NAME="IDX269"></A> +Each time this parameter is referenced, a random integer +between 0 and 32767 is generated. Assigning a value to this +variable seeds the random number generator. +<P> + +<A NAME="IDX270"></A> +<DT><CODE>REPLY</CODE> +<DD><A NAME="IDX271"></A> +The default variable for the <CODE>read</CODE> builtin. +<P> + +<A NAME="IDX272"></A> +<DT><CODE>SECONDS</CODE> +<DD><A NAME="IDX273"></A> +This variable expands to the number of seconds since the +shell was started. Assignment to this variable resets +the count to the value assigned, and the expanded value +becomes the value assigned plus the number of seconds +since the assignment. +<P> + +<A NAME="IDX274"></A> +<DT><CODE>SHELL</CODE> +<DD><A NAME="IDX275"></A> +The full pathname to the shell is kept in this environment variable. +If it is not set when the shell starts, +Bash assigns to it the full pathname of the current user's login shell. +<P> + +<A NAME="IDX276"></A> +<DT><CODE>SHELLOPTS</CODE> +<DD><A NAME="IDX277"></A> +A colon-separated list of enabled shell options. Each word in +the list is a valid argument for the <SAMP>`-o'</SAMP> option to the +<CODE>set</CODE> builtin command (see section <A HREF="bashref.html#SEC62">4.3.1 The Set Builtin</A>). +The options appearing in <CODE>SHELLOPTS</CODE> are those reported +as <SAMP>`on'</SAMP> by <SAMP>`set -o'</SAMP>. +If this variable is in the environment when Bash +starts up, each shell option in the list will be enabled before +reading any startup files. This variable is readonly. +<P> + +<A NAME="IDX278"></A> +<DT><CODE>SHLVL</CODE> +<DD><A NAME="IDX279"></A> +Incremented by one each time a new instance of Bash is started. This is +intended to be a count of how deeply your Bash shells are nested. +<P> + +<A NAME="IDX280"></A> +<DT><CODE>TIMEFORMAT</CODE> +<DD><A NAME="IDX281"></A> +The value of this parameter is used as a format string specifying +how the timing information for pipelines prefixed with the <CODE>time</CODE> +reserved word should be displayed. +The <SAMP>`%'</SAMP> character introduces an +escape sequence that is expanded to a time value or other +information. +The escape sequences and their meanings are as +follows; the braces denote optional portions. +<P> + +<DL COMPACT> + +<DT><CODE>%%</CODE> +<DD>A literal <SAMP>`%'</SAMP>. +<P> + +<DT><CODE>%[<VAR>p</VAR>][l]R</CODE> +<DD>The elapsed time in seconds. +<P> + +<DT><CODE>%[<VAR>p</VAR>][l]U</CODE> +<DD>The number of CPU seconds spent in user mode. +<P> + +<DT><CODE>%[<VAR>p</VAR>][l]S</CODE> +<DD>The number of CPU seconds spent in system mode. +<P> + +<DT><CODE>%P</CODE> +<DD>The CPU percentage, computed as (%U + %S) / %R. +</DL> +<P> + +The optional <VAR>p</VAR> is a digit specifying the precision, the number of +fractional digits after a decimal point. +A value of 0 causes no decimal point or fraction to be output. +At most three places after the decimal point may be specified; values +of <VAR>p</VAR> greater than 3 are changed to 3. +If <VAR>p</VAR> is not specified, the value 3 is used. +</P><P> + +The optional <CODE>l</CODE> specifies a longer format, including minutes, of +the form <VAR>MM</VAR>m<VAR>SS</VAR>.<VAR>FF</VAR>s. +The value of <VAR>p</VAR> determines whether or not the fraction is included. +</P><P> + +If this variable is not set, Bash acts as if it had the value +<TABLE><tr><td> </td><td class=example><pre><CODE>$'\nreal\t%3lR\nuser\t%3lU\nsys\t%3lS'</CODE> +</pre></td></tr></table>If the value is null, no timing information is displayed. +A trailing newline is added when the format string is displayed. +</P><P> + +<A NAME="IDX282"></A> +<DT><CODE>TMOUT</CODE> +<DD><A NAME="IDX283"></A> +If set to a value greater than zero, <CODE>TMOUT</CODE> is treated as the +default timeout for the <CODE>read</CODE> builtin (see section <A HREF="bashref.html#SEC60">4.2 Bash Builtin Commands</A>). +The <CODE>select</CODE> command (see section <A HREF="bashref.html#SEC21">3.2.4.2 Conditional Constructs</A>) terminates +if input does not arrive after <CODE>TMOUT</CODE> seconds when input is coming +from a terminal. +<P> + +In an interactive shell, the value is interpreted as +the number of seconds to wait for input after issuing the primary +prompt when the shell is interactive. +Bash terminates after that number of seconds if input does +not arrive. +</P><P> + +<A NAME="IDX284"></A> +<DT><CODE>TMPDIR</CODE> +<DD><A NAME="IDX285"></A> +If set, Bash uses its value as the name of a directory in which +Bash creates temporary files for the shell's use. +<P> + +<A NAME="IDX286"></A> +<DT><CODE>UID</CODE> +<DD><A NAME="IDX287"></A> +The numeric real user id of the current user. This variable is readonly. +<P> + +</DL> +<P> + +<A NAME="Bash Features"></A> +<HR SIZE="6"> +<A NAME="SEC68"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC67"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC69"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC91"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC91"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H1> 6. Bash Features </H1> +<!--docid::SEC68::--> +<P> + +This section describes features unique to Bash. +</P><P> + +<BLOCKQUOTE><TABLE BORDER=0 CELLSPACING=0> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC69">6.1 Invoking Bash</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Command line options that you can give + to Bash.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC70">6.2 Bash Startup Files</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">When and how Bash executes scripts.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC78">6.3 Interactive Shells</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">What an interactive shell is.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC82">6.4 Bash Conditional Expressions</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Primitives used in composing expressions for + the <CODE>test</CODE> builtin.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC83">6.5 Shell Arithmetic</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Arithmetic on shell variables.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC84">6.6 Aliases</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Substituting one command for another.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC85">6.7 Arrays</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Array Variables.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC86">6.8 The Directory Stack</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">History of visited directories.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC88">6.9 Controlling the Prompt</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Controlling the PS1 string.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC89">6.10 The Restricted Shell</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">A more controlled mode of shell execution.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC90">6.11 Bash POSIX Mode</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Making Bash behave more closely to what + the POSIX standard specifies.</TD></TR> +</TABLE></BLOCKQUOTE> +<P> + +<A NAME="Invoking Bash"></A> +<HR SIZE="6"> +<A NAME="SEC69"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC68"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC70"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC68"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC68"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC91"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H2> 6.1 Invoking Bash </H2> +<!--docid::SEC69::--> +<P> + +<TABLE><tr><td> </td><td class=example><pre>bash [long-opt] [-ir] [-abefhkmnptuvxdBCDHP] [-o <VAR>option</VAR>] [-O <VAR>shopt_option</VAR>] [<VAR>argument</VAR> <small>...</small>] +bash [long-opt] [-abefhkmnptuvxdBCDHP] [-o <VAR>option</VAR>] [-O <VAR>shopt_option</VAR>] -c <VAR>string</VAR> [<VAR>argument</VAR> <small>...</small>] +bash [long-opt] -s [-abefhkmnptuvxdBCDHP] [-o <VAR>option</VAR>] [-O <VAR>shopt_option</VAR>] [<VAR>argument</VAR> <small>...</small>] +</pre></td></tr></table></P><P> + +In addition to the single-character shell command-line options +(see section <A HREF="bashref.html#SEC62">4.3.1 The Set Builtin</A>), there are several multi-character +options that you can use. These options must appear on the command +line before the single-character options to be recognized. +</P><P> + +<DL COMPACT> +<DT><CODE>--debugger</CODE> +<DD>Arrange for the debugger profile to be executed before the shell +starts. Turns on extended debugging mode (see <A HREF="bashref.html#SEC63">4.3.2 The Shopt Builtin</A> +for a description of the <CODE>extdebug</CODE> option to the <CODE>shopt</CODE> +builtin) and shell function tracing +(see <A HREF="bashref.html#SEC62">4.3.1 The Set Builtin</A> for a description of the <CODE>-o functrace</CODE> +option). +<P> + +<DT><CODE>--dump-po-strings</CODE> +<DD>A list of all double-quoted strings preceded by <SAMP>`$'</SAMP> +is printed on the standard output +in the GNU <CODE>gettext</CODE> PO (portable object) file format. +Equivalent to <SAMP>`-D'</SAMP> except for the output format. +<P> + +<DT><CODE>--dump-strings</CODE> +<DD>Equivalent to <SAMP>`-D'</SAMP>. +<P> + +<DT><CODE>--help</CODE> +<DD>Display a usage message on standard output and exit successfully. +<P> + +<DT><CODE>--init-file <VAR>filename</VAR></CODE> +<DD><DT><CODE>--rcfile <VAR>filename</VAR></CODE> +<DD>Execute commands from <VAR>filename</VAR> (instead of <TT>`~/.bashrc'</TT>) +in an interactive shell. +<P> + +<DT><CODE>--login</CODE> +<DD>Equivalent to <SAMP>`-l'</SAMP>. +<P> + +<DT><CODE>--noediting</CODE> +<DD>Do not use the GNU Readline library (see section <A HREF="bashref.html#SEC95">8. Command Line Editing</A>) +to read command lines when the shell is interactive. +<P> + +<DT><CODE>--noprofile</CODE> +<DD>Don't load the system-wide startup file <TT>`/etc/profile'</TT> +or any of the personal initialization files +<TT>`~/.bash_profile'</TT>, <TT>`~/.bash_login'</TT>, or <TT>`~/.profile'</TT> +when Bash is invoked as a login shell. +<P> + +<DT><CODE>--norc</CODE> +<DD>Don't read the <TT>`~/.bashrc'</TT> initialization file in an +interactive shell. This is on by default if the shell is +invoked as <CODE>sh</CODE>. +<P> + +<DT><CODE>--posix</CODE> +<DD>Change the behavior of Bash where the default operation differs +from the POSIX standard to match the standard. This +is intended to make Bash behave as a strict superset of that +standard. See section <A HREF="bashref.html#SEC90">6.11 Bash POSIX Mode</A>, for a description of the Bash +POSIX mode. +<P> + +<DT><CODE>--restricted</CODE> +<DD>Make the shell a restricted shell (see section <A HREF="bashref.html#SEC89">6.10 The Restricted Shell</A>). +<P> + +<DT><CODE>--verbose</CODE> +<DD>Equivalent to <SAMP>`-v'</SAMP>. Print shell input lines as they're read. +<P> + +<DT><CODE>--version</CODE> +<DD>Show version information for this instance of +Bash on the standard output and exit successfully. +<P> + +</DL> +<P> + +There are several single-character options that may be supplied at +invocation which are not available with the <CODE>set</CODE> builtin. +</P><P> + +<DL COMPACT> +<DT><CODE>-c <VAR>string</VAR></CODE> +<DD>Read and execute commands from <VAR>string</VAR> after processing the +options, then exit. Any remaining arguments are assigned to the +positional parameters, starting with <CODE>$0</CODE>. +<P> + +<DT><CODE>-i</CODE> +<DD>Force the shell to run interactively. Interactive shells are +described in <A HREF="bashref.html#SEC78">6.3 Interactive Shells</A>. +<P> + +<DT><CODE>-l</CODE> +<DD>Make this shell act as if it had been directly invoked by login. +When the shell is interactive, this is equivalent to starting a +login shell with <SAMP>`exec -l bash'</SAMP>. +When the shell is not interactive, the login shell startup files will +be executed. +<SAMP>`exec bash -l'</SAMP> or <SAMP>`exec bash --login'</SAMP> +will replace the current shell with a Bash login shell. +See section <A HREF="bashref.html#SEC70">6.2 Bash Startup Files</A>, for a description of the special behavior +of a login shell. +<P> + +<DT><CODE>-r</CODE> +<DD>Make the shell a restricted shell (see section <A HREF="bashref.html#SEC89">6.10 The Restricted Shell</A>). +<P> + +<DT><CODE>-s</CODE> +<DD>If this option is present, or if no arguments remain after option +processing, then commands are read from the standard input. +This option allows the positional parameters to be set +when invoking an interactive shell. +<P> + +<DT><CODE>-D</CODE> +<DD>A list of all double-quoted strings preceded by <SAMP>`$'</SAMP> +is printed on the standard output. +These are the strings that +are subject to language translation when the current locale +is not <CODE>C</CODE> or <CODE>POSIX</CODE> (see section <A HREF="bashref.html#SEC13">3.1.2.5 Locale-Specific Translation</A>). +This implies the <SAMP>`-n'</SAMP> option; no commands will be executed. +<P> + +<DT><CODE>[-+]O [<VAR>shopt_option</VAR>]</CODE> +<DD><VAR>shopt_option</VAR> is one of the shell options accepted by the +<CODE>shopt</CODE> builtin (see section <A HREF="bashref.html#SEC63">4.3.2 The Shopt Builtin</A>). +If <VAR>shopt_option</VAR> is present, <SAMP>`-O'</SAMP> sets the value of that option; +<SAMP>`+O'</SAMP> unsets it. +If <VAR>shopt_option</VAR> is not supplied, the names and values of the shell +options accepted by <CODE>shopt</CODE> are printed on the standard output. +If the invocation option is <SAMP>`+O'</SAMP>, the output is displayed in a format +that may be reused as input. +<P> + +<DT><CODE>--</CODE> +<DD>A <CODE>--</CODE> signals the end of options and disables further option +processing. +Any arguments after the <CODE>--</CODE> are treated as filenames and arguments. +<P> + +</DL> +<P> + +<A NAME="IDX288"></A> +A <EM>login</EM> shell is one whose first character of argument zero is +<SAMP>`-'</SAMP>, or one invoked with the <SAMP>`--login'</SAMP> option. +</P><P> + +<A NAME="IDX289"></A> +An <EM>interactive</EM> shell is one started without non-option arguments, +unless <SAMP>`-s'</SAMP> is specified, +without specifying the <SAMP>`-c'</SAMP> option, and whose input and output are both +connected to terminals (as determined by <CODE>isatty(3)</CODE>), or one +started with the <SAMP>`-i'</SAMP> option. See section <A HREF="bashref.html#SEC78">6.3 Interactive Shells</A>, for more +information. +</P><P> + +If arguments remain after option processing, and neither the +<SAMP>`-c'</SAMP> nor the <SAMP>`-s'</SAMP> +option has been supplied, the first argument is assumed to +be the name of a file containing shell commands (see section <A HREF="bashref.html#SEC57">3.8 Shell Scripts</A>). +When Bash is invoked in this fashion, <CODE>$0</CODE> +is set to the name of the file, and the positional parameters +are set to the remaining arguments. +Bash reads and executes commands from this file, then exits. +Bash's exit status is the exit status of the last command executed +in the script. If no commands are executed, the exit status is 0. +</P><P> + +<A NAME="Bash Startup Files"></A> +<HR SIZE="6"> +<A NAME="SEC70"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC69"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC78"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC78"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC68"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC91"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H2> 6.2 Bash Startup Files </H2> +<!--docid::SEC70::--> +<P> + +This section describes how Bash executes its startup files. +If any of the files exist but cannot be read, Bash reports an error. +Tildes are expanded in file names as described above under +Tilde Expansion (see section <A HREF="bashref.html#SEC30">3.5.2 Tilde Expansion</A>). +</P><P> + +Interactive shells are described in <A HREF="bashref.html#SEC78">6.3 Interactive Shells</A>. +</P><P> + +<A NAME="SEC71"></A> +<H4> Invoked as an interactive login shell, or with <SAMP>`--login'</SAMP> </H4> +<!--docid::SEC71::--> +<P> + +When Bash is invoked as an interactive login shell, or as a +non-interactive shell with the <SAMP>`--login'</SAMP> option, it first reads and +executes commands from the file <TT>`/etc/profile'</TT>, if that file exists. +After reading that file, it looks for <TT>`~/.bash_profile'</TT>, +<TT>`~/.bash_login'</TT>, and <TT>`~/.profile'</TT>, in that order, and reads +and executes commands from the first one that exists and is readable. +The <SAMP>`--noprofile'</SAMP> option may be used when the shell is started to +inhibit this behavior. +</P><P> + +When a login shell exits, Bash reads and executes commands from +the file <TT>`~/.bash_logout'</TT>, if it exists. +</P><P> + +<A NAME="SEC72"></A> +<H4> Invoked as an interactive non-login shell </H4> +<!--docid::SEC72::--> +<P> + +When an interactive shell that is not a login shell is started, Bash +reads and executes commands from <TT>`~/.bashrc'</TT>, if that file exists. +This may be inhibited by using the <SAMP>`--norc'</SAMP> option. +The <SAMP>`--rcfile <VAR>file</VAR>'</SAMP> option will force Bash to read and +execute commands from <VAR>file</VAR> instead of <TT>`~/.bashrc'</TT>. +</P><P> + +So, typically, your <TT>`~/.bash_profile'</TT> contains the line +<TABLE><tr><td> </td><td class=example><pre><CODE>if [ -f ~/.bashrc ]; then . ~/.bashrc; fi</CODE> +</pre></td></tr></table>after (or before) any login-specific initializations. +</P><P> + +<A NAME="SEC73"></A> +<H4> Invoked non-interactively </H4> +<!--docid::SEC73::--> +<P> + +When Bash is started non-interactively, to run a shell script, +for example, it looks for the variable <CODE>BASH_ENV</CODE> in the environment, +expands its value if it appears there, and uses the expanded value as +the name of a file to read and execute. Bash behaves as if the +following command were executed: +<TABLE><tr><td> </td><td class=example><pre><CODE>if [ -n "$BASH_ENV" ]; then . "$BASH_ENV"; fi</CODE> +</pre></td></tr></table>but the value of the <CODE>PATH</CODE> variable is not used to search for the +file name. +</P><P> + +As noted above, if a non-interactive shell is invoked with the +<SAMP>`--login'</SAMP> option, Bash attempts to read and execute commands from the +login shell startup files. +</P><P> + +<A NAME="SEC74"></A> +<H4> Invoked with name <CODE>sh</CODE> </H4> +<!--docid::SEC74::--> +<P> + +If Bash is invoked with the name <CODE>sh</CODE>, it tries to mimic the +startup behavior of historical versions of <CODE>sh</CODE> as closely as +possible, while conforming to the POSIX standard as well. +</P><P> + +When invoked as an interactive login shell, or as a non-interactive +shell with the <SAMP>`--login'</SAMP> option, it first attempts to read +and execute commands from <TT>`/etc/profile'</TT> and <TT>`~/.profile'</TT>, in +that order. +The <SAMP>`--noprofile'</SAMP> option may be used to inhibit this behavior. +When invoked as an interactive shell with the name <CODE>sh</CODE>, Bash +looks for the variable <CODE>ENV</CODE>, expands its value if it is defined, +and uses the expanded value as the name of a file to read and execute. +Since a shell invoked as <CODE>sh</CODE> does not attempt to read and execute +commands from any other startup files, the <SAMP>`--rcfile'</SAMP> option has +no effect. +A non-interactive shell invoked with the name <CODE>sh</CODE> does not attempt +to read any other startup files. +</P><P> + +When invoked as <CODE>sh</CODE>, Bash enters POSIX mode after +the startup files are read. +</P><P> + +<A NAME="SEC75"></A> +<H4> Invoked in POSIX mode </H4> +<!--docid::SEC75::--> +<P> + +When Bash is started in POSIX mode, as with the +<SAMP>`--posix'</SAMP> command line option, it follows the POSIX standard +for startup files. +In this mode, interactive shells expand the <CODE>ENV</CODE> variable +and commands are read and executed from the file whose name is the +expanded value. +No other startup files are read. +</P><P> + +<A NAME="SEC76"></A> +<H4> Invoked by remote shell daemon </H4> +<!--docid::SEC76::--> +<P> + +Bash attempts to determine when it is being run with its standard input +connected to a a network connection, as if by the remote shell +daemon, usually <CODE>rshd</CODE>, or the secure shell daemon <CODE>sshd</CODE>. +If Bash determines it is being run in +this fashion, it reads and executes commands from <TT>`~/.bashrc'</TT>, if that +file exists and is readable. +It will not do this if invoked as <CODE>sh</CODE>. +The <SAMP>`--norc'</SAMP> option may be used to inhibit this behavior, and the +<SAMP>`--rcfile'</SAMP> option may be used to force another file to be read, but +<CODE>rshd</CODE> does not generally invoke the shell with those options or +allow them to be specified. +</P><P> + +<A NAME="SEC77"></A> +<H4> Invoked with unequal effective and real UID/GIDs </H4> +<!--docid::SEC77::--> +<P> + +If Bash is started with the effective user (group) id not equal to the +real user (group) id, and the <CODE>-p</CODE> option is not supplied, no startup +files are read, shell functions are not inherited from the environment, +the <CODE>SHELLOPTS</CODE>, <CODE>BASHOPTS</CODE>, <CODE>CDPATH</CODE>, and <CODE>GLOBIGNORE</CODE> +variables, if they appear in the environment, are ignored, and the effective +user id is set to the real user id. +If the <CODE>-p</CODE> option is supplied at invocation, the startup behavior is +the same, but the effective user id is not reset. +</P><P> + +<A NAME="Interactive Shells"></A> +<HR SIZE="6"> +<A NAME="SEC78"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC70"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC79"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC82"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC68"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC82"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H2> 6.3 Interactive Shells </H2> +<!--docid::SEC78::--> +<P> + +<BLOCKQUOTE><TABLE BORDER=0 CELLSPACING=0> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC79">6.3.1 What is an Interactive Shell?</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">What determines whether a shell is Interactive.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC80">6.3.2 Is this Shell Interactive?</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">How to tell if a shell is interactive.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC81">6.3.3 Interactive Shell Behavior</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">What changes in a interactive shell?</TD></TR> +</TABLE></BLOCKQUOTE> +<P> + +<A NAME="What is an Interactive Shell?"></A> +<HR SIZE="6"> +<A NAME="SEC79"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC78"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC80"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC82"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC78"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC82"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 6.3.1 What is an Interactive Shell? </H3> +<!--docid::SEC79::--> +<P> + +An interactive shell +is one started without non-option arguments, unless <SAMP>`-s'</SAMP> is +specified, without specifying the <SAMP>`-c'</SAMP> option, and +whose input and error output are both +connected to terminals (as determined by <CODE>isatty(3)</CODE>), +or one started with the <SAMP>`-i'</SAMP> option. +</P><P> + +An interactive shell generally reads from and writes to a user's +terminal. +</P><P> + +The <SAMP>`-s'</SAMP> invocation option may be used to set the positional parameters +when an interactive shell is started. +</P><P> + +<A NAME="Is this Shell Interactive?"></A> +<HR SIZE="6"> +<A NAME="SEC80"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC79"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC81"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC81"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC78"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC82"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 6.3.2 Is this Shell Interactive? </H3> +<!--docid::SEC80::--> +<P> + +To determine within a startup script whether or not Bash is +running interactively, +test the value of the <SAMP>`-'</SAMP> special parameter. +It contains <CODE>i</CODE> when the shell is interactive. For example: +</P><P> + +<TABLE><tr><td> </td><td class=example><pre>case "$-" in +*i*) echo This shell is interactive ;; +*) echo This shell is not interactive ;; +esac +</pre></td></tr></table></P><P> + +Alternatively, startup scripts may examine the variable +<CODE>PS1</CODE>; it is unset in non-interactive shells, and set in +interactive shells. Thus: +</P><P> + +<TABLE><tr><td> </td><td class=example><pre>if [ -z "$PS1" ]; then + echo This shell is not interactive +else + echo This shell is interactive +fi +</pre></td></tr></table></P><P> + +<A NAME="Interactive Shell Behavior"></A> +<HR SIZE="6"> +<A NAME="SEC81"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC80"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC82"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC82"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC78"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC82"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 6.3.3 Interactive Shell Behavior </H3> +<!--docid::SEC81::--> +<P> + +When the shell is running interactively, it changes its behavior in +several ways. +</P><P> + +<OL> +<LI> +Startup files are read and executed as described in <A HREF="bashref.html#SEC70">6.2 Bash Startup Files</A>. +<P> + +<LI> +Job Control (see section <A HREF="bashref.html#SEC91">7. Job Control</A>) is enabled by default. When job +control is in effect, Bash ignores the keyboard-generated job control +signals <CODE>SIGTTIN</CODE>, <CODE>SIGTTOU</CODE>, and <CODE>SIGTSTP</CODE>. +<P> + +<LI> +Bash expands and displays <CODE>PS1</CODE> before reading the first line +of a command, and expands and displays <CODE>PS2</CODE> before reading the +second and subsequent lines of a multi-line command. +<P> + +<LI> +Bash executes the value of the <CODE>PROMPT_COMMAND</CODE> variable as a command +before printing the primary prompt, <CODE>$PS1</CODE> +(see section <A HREF="bashref.html#SEC67">5.2 Bash Variables</A>). +<P> + +<LI> +Readline (see section <A HREF="bashref.html#SEC95">8. Command Line Editing</A>) is used to read commands from +the user's terminal. +<P> + +<LI> +Bash inspects the value of the <CODE>ignoreeof</CODE> option to <CODE>set -o</CODE> +instead of exiting immediately when it receives an <CODE>EOF</CODE> on its +standard input when reading a command (see section <A HREF="bashref.html#SEC62">4.3.1 The Set Builtin</A>). +<P> + +<LI> +Command history (see section <A HREF="bashref.html#SEC120">9.1 Bash History Facilities</A>) +and history expansion (see section <A HREF="bashref.html#SEC122">9.3 History Expansion</A>) +are enabled by default. +Bash will save the command history to the file named by <CODE>$HISTFILE</CODE> +when an interactive shell exits. +<P> + +<LI> +Alias expansion (see section <A HREF="bashref.html#SEC84">6.6 Aliases</A>) is performed by default. +<P> + +<LI> +In the absence of any traps, Bash ignores <CODE>SIGTERM</CODE> +(see section <A HREF="bashref.html#SEC56">3.7.6 Signals</A>). +<P> + +<LI> +In the absence of any traps, <CODE>SIGINT</CODE> is caught and handled +((see section <A HREF="bashref.html#SEC56">3.7.6 Signals</A>). +<CODE>SIGINT</CODE> will interrupt some shell builtins. +<P> + +<LI> +An interactive login shell sends a <CODE>SIGHUP</CODE> to all jobs on exit +if the <CODE>huponexit</CODE> shell option has been enabled (see section <A HREF="bashref.html#SEC56">3.7.6 Signals</A>). +<P> + +<LI> +The <SAMP>`-n'</SAMP> invocation option is ignored, and <SAMP>`set -n'</SAMP> has +no effect (see section <A HREF="bashref.html#SEC62">4.3.1 The Set Builtin</A>). +<P> + +<LI> +Bash will check for mail periodically, depending on the values of the +<CODE>MAIL</CODE>, <CODE>MAILPATH</CODE>, and <CODE>MAILCHECK</CODE> shell variables +(see section <A HREF="bashref.html#SEC67">5.2 Bash Variables</A>). +<P> + +<LI> +Expansion errors due to references to unbound shell variables after +<SAMP>`set -u'</SAMP> has been enabled will not cause the shell to exit +(see section <A HREF="bashref.html#SEC62">4.3.1 The Set Builtin</A>). +<P> + +<LI> +The shell will not exit on expansion errors caused by <VAR>var</VAR> being unset +or null in <CODE>${<VAR>var</VAR>:?<VAR>word</VAR>}</CODE> expansions +(see section <A HREF="bashref.html#SEC31">3.5.3 Shell Parameter Expansion</A>). +<P> + +<LI> +Redirection errors encountered by shell builtins will not cause the +shell to exit. +<P> + +<LI> +When running in POSIX mode, a special builtin returning an error +status will not cause the shell to exit (see section <A HREF="bashref.html#SEC90">6.11 Bash POSIX Mode</A>). +<P> + +<LI> +A failed <CODE>exec</CODE> will not cause the shell to exit +(see section <A HREF="bashref.html#SEC59">4.1 Bourne Shell Builtins</A>). +<P> + +<LI> +Parser syntax errors will not cause the shell to exit. +<P> + +<LI> +Simple spelling correction for directory arguments to the <CODE>cd</CODE> +builtin is enabled by default (see the description of the <CODE>cdspell</CODE> +option to the <CODE>shopt</CODE> builtin in <A HREF="bashref.html#SEC63">4.3.2 The Shopt Builtin</A>). +<P> + +<LI> +The shell will check the value of the <CODE>TMOUT</CODE> variable and exit +if a command is not read within the specified number of seconds after +printing <CODE>$PS1</CODE> (see section <A HREF="bashref.html#SEC67">5.2 Bash Variables</A>). +<P> + +</OL> +<P> + +<A NAME="Bash Conditional Expressions"></A> +<HR SIZE="6"> +<A NAME="SEC82"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC81"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC83"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC83"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC68"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC91"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H2> 6.4 Bash Conditional Expressions </H2> +<!--docid::SEC82::--> +<P> + +Conditional expressions are used by the <CODE>[[</CODE> compound command +and the <CODE>test</CODE> and <CODE>[</CODE> builtin commands. +</P><P> + +Expressions may be unary or binary. +Unary expressions are often used to examine the status of a file. +There are string operators and numeric comparison operators as well. +If the <VAR>file</VAR> argument to one of the primaries is of the form +<TT>`/dev/fd/<VAR>N</VAR>'</TT>, then file descriptor <VAR>N</VAR> is checked. +If the <VAR>file</VAR> argument to one of the primaries is one of +<TT>`/dev/stdin'</TT>, <TT>`/dev/stdout'</TT>, or <TT>`/dev/stderr'</TT>, file +descriptor 0, 1, or 2, respectively, is checked. +</P><P> + +When used with <SAMP>`[['</SAMP>, The <SAMP>`<'</SAMP> and <SAMP>`>'</SAMP> operators sort +lexicographically using the current locale. +</P><P> + +Unless otherwise specified, primaries that operate on files follow symbolic +links and operate on the target of the link, rather than the link itself. +</P><P> + +<DL COMPACT> +<DT><CODE>-a <VAR>file</VAR></CODE> +<DD>True if <VAR>file</VAR> exists. +<P> + +<DT><CODE>-b <VAR>file</VAR></CODE> +<DD>True if <VAR>file</VAR> exists and is a block special file. +<P> + +<DT><CODE>-c <VAR>file</VAR></CODE> +<DD>True if <VAR>file</VAR> exists and is a character special file. +<P> + +<DT><CODE>-d <VAR>file</VAR></CODE> +<DD>True if <VAR>file</VAR> exists and is a directory. +<P> + +<DT><CODE>-e <VAR>file</VAR></CODE> +<DD>True if <VAR>file</VAR> exists. +<P> + +<DT><CODE>-f <VAR>file</VAR></CODE> +<DD>True if <VAR>file</VAR> exists and is a regular file. +<P> + +<DT><CODE>-g <VAR>file</VAR></CODE> +<DD>True if <VAR>file</VAR> exists and its set-group-id bit is set. +<P> + +<DT><CODE>-h <VAR>file</VAR></CODE> +<DD>True if <VAR>file</VAR> exists and is a symbolic link. +<P> + +<DT><CODE>-k <VAR>file</VAR></CODE> +<DD>True if <VAR>file</VAR> exists and its "sticky" bit is set. +<P> + +<DT><CODE>-p <VAR>file</VAR></CODE> +<DD>True if <VAR>file</VAR> exists and is a named pipe (FIFO). +<P> + +<DT><CODE>-r <VAR>file</VAR></CODE> +<DD>True if <VAR>file</VAR> exists and is readable. +<P> + +<DT><CODE>-s <VAR>file</VAR></CODE> +<DD>True if <VAR>file</VAR> exists and has a size greater than zero. +<P> + +<DT><CODE>-t <VAR>fd</VAR></CODE> +<DD>True if file descriptor <VAR>fd</VAR> is open and refers to a terminal. +<P> + +<DT><CODE>-u <VAR>file</VAR></CODE> +<DD>True if <VAR>file</VAR> exists and its set-user-id bit is set. +<P> + +<DT><CODE>-w <VAR>file</VAR></CODE> +<DD>True if <VAR>file</VAR> exists and is writable. +<P> + +<DT><CODE>-x <VAR>file</VAR></CODE> +<DD>True if <VAR>file</VAR> exists and is executable. +<P> + +<DT><CODE>-O <VAR>file</VAR></CODE> +<DD>True if <VAR>file</VAR> exists and is owned by the effective user id. +<P> + +<DT><CODE>-G <VAR>file</VAR></CODE> +<DD>True if <VAR>file</VAR> exists and is owned by the effective group id. +<P> + +<DT><CODE>-L <VAR>file</VAR></CODE> +<DD>True if <VAR>file</VAR> exists and is a symbolic link. +<P> + +<DT><CODE>-S <VAR>file</VAR></CODE> +<DD>True if <VAR>file</VAR> exists and is a socket. +<P> + +<DT><CODE>-N <VAR>file</VAR></CODE> +<DD>True if <VAR>file</VAR> exists and has been modified since it was last read. +<P> + +<DT><CODE><VAR>file1</VAR> -nt <VAR>file2</VAR></CODE> +<DD>True if <VAR>file1</VAR> is newer (according to modification date) +than <VAR>file2</VAR>, or if <VAR>file1</VAR> exists and <VAR>file2</VAR> does not. +<P> + +<DT><CODE><VAR>file1</VAR> -ot <VAR>file2</VAR></CODE> +<DD>True if <VAR>file1</VAR> is older than <VAR>file2</VAR>, +or if <VAR>file2</VAR> exists and <VAR>file1</VAR> does not. +<P> + +<DT><CODE><VAR>file1</VAR> -ef <VAR>file2</VAR></CODE> +<DD>True if <VAR>file1</VAR> and <VAR>file2</VAR> refer to the same device and +inode numbers. +<P> + +<DT><CODE>-o <VAR>optname</VAR></CODE> +<DD>True if shell option <VAR>optname</VAR> is enabled. +The list of options appears in the description of the <SAMP>`-o'</SAMP> +option to the <CODE>set</CODE> builtin (see section <A HREF="bashref.html#SEC62">4.3.1 The Set Builtin</A>). +<P> + +<DT><CODE>-z <VAR>string</VAR></CODE> +<DD>True if the length of <VAR>string</VAR> is zero. +<P> + +<DT><CODE>-n <VAR>string</VAR></CODE> +<DD><DT><CODE><VAR>string</VAR></CODE> +<DD>True if the length of <VAR>string</VAR> is non-zero. +<P> + +<DT><CODE><VAR>string1</VAR> == <VAR>string2</VAR></CODE> +<DD><DT><CODE><VAR>string1</VAR> = <VAR>string2</VAR></CODE> +<DD>True if the strings are equal. +<SAMP>`='</SAMP> should be used with the <CODE>test</CODE> command for POSIX conformance. +<P> + +<DT><CODE><VAR>string1</VAR> != <VAR>string2</VAR></CODE> +<DD>True if the strings are not equal. +<P> + +<DT><CODE><VAR>string1</VAR> < <VAR>string2</VAR></CODE> +<DD>True if <VAR>string1</VAR> sorts before <VAR>string2</VAR> lexicographically. +<P> + +<DT><CODE><VAR>string1</VAR> > <VAR>string2</VAR></CODE> +<DD>True if <VAR>string1</VAR> sorts after <VAR>string2</VAR> lexicographically. +<P> + +<DT><CODE><VAR>arg1</VAR> OP <VAR>arg2</VAR></CODE> +<DD><CODE>OP</CODE> is one of +<SAMP>`-eq'</SAMP>, <SAMP>`-ne'</SAMP>, <SAMP>`-lt'</SAMP>, <SAMP>`-le'</SAMP>, <SAMP>`-gt'</SAMP>, or <SAMP>`-ge'</SAMP>. +These arithmetic binary operators return true if <VAR>arg1</VAR> +is equal to, not equal to, less than, less than or equal to, +greater than, or greater than or equal to <VAR>arg2</VAR>, +respectively. <VAR>Arg1</VAR> and <VAR>arg2</VAR> +may be positive or negative integers. +<P> + +</DL> +<P> + +<A NAME="Shell Arithmetic"></A> +<HR SIZE="6"> +<A NAME="SEC83"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC82"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC84"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC84"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC68"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC91"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H2> 6.5 Shell Arithmetic </H2> +<!--docid::SEC83::--> +<P> + +The shell allows arithmetic expressions to be evaluated, as one of +the shell expansions or by the <CODE>let</CODE> and the <SAMP>`-i'</SAMP> option +to the <CODE>declare</CODE> builtins. +</P><P> + +Evaluation is done in fixed-width integers with no check for overflow, +though division by 0 is trapped and flagged as an error. +The operators and their precedence, associativity, and values +are the same as in the C language. +The following list of operators is grouped into levels of +equal-precedence operators. +The levels are listed in order of decreasing precedence. +</P><P> + +<DL COMPACT> + +<DT><CODE><VAR>id</VAR>++ <VAR>id</VAR>--</CODE> +<DD>variable post-increment and post-decrement +<P> + +<DT><CODE>++<VAR>id</VAR> --<VAR>id</VAR></CODE> +<DD>variable pre-increment and pre-decrement +<P> + +<DT><CODE>- +</CODE> +<DD>unary minus and plus +<P> + +<DT><CODE>! ~</CODE> +<DD>logical and bitwise negation +<P> + +<DT><CODE>**</CODE> +<DD>exponentiation +<P> + +<DT><CODE>* / %</CODE> +<DD>multiplication, division, remainder +<P> + +<DT><CODE>+ -</CODE> +<DD>addition, subtraction +<P> + +<DT><CODE><< >></CODE> +<DD>left and right bitwise shifts +<P> + +<DT><CODE><= >= < ></CODE> +<DD>comparison +<P> + +<DT><CODE>== !=</CODE> +<DD>equality and inequality +<P> + +<DT><CODE>&</CODE> +<DD>bitwise AND +<P> + +<DT><CODE>^</CODE> +<DD>bitwise exclusive OR +<P> + +<DT><CODE>|</CODE> +<DD>bitwise OR +<P> + +<DT><CODE>&&</CODE> +<DD>logical AND +<P> + +<DT><CODE>||</CODE> +<DD>logical OR +<P> + +<DT><CODE>expr ? expr : expr</CODE> +<DD>conditional operator +<P> + +<DT><CODE>= *= /= %= += -= <<= >>= &= ^= |=</CODE> +<DD>assignment +<P> + +<DT><CODE>expr1 , expr2</CODE> +<DD>comma +</DL> +<P> + +Shell variables are allowed as operands; parameter expansion is +performed before the expression is evaluated. +Within an expression, shell variables may also be referenced by name +without using the parameter expansion syntax. +A shell variable that is null or unset evaluates to 0 when referenced +by name without using the parameter expansion syntax. +The value of a variable is evaluated as an arithmetic expression +when it is referenced, or when a variable which has been given the +<VAR>integer</VAR> attribute using <SAMP>`declare -i'</SAMP> is assigned a value. +A null value evaluates to 0. +A shell variable need not have its integer attribute turned on +to be used in an expression. +</P><P> + +Constants with a leading 0 are interpreted as octal numbers. +A leading <SAMP>`0x'</SAMP> or <SAMP>`0X'</SAMP> denotes hexadecimal. Otherwise, +numbers take the form [<VAR>base</VAR><CODE>#</CODE>]<VAR>n</VAR>, where <VAR>base</VAR> +is a decimal number between 2 and 64 representing the arithmetic +base, and <VAR>n</VAR> is a number in that base. If <VAR>base</VAR><CODE>#</CODE> is +omitted, then base 10 is used. +The digits greater than 9 are represented by the lowercase letters, +the uppercase letters, <SAMP>`@'</SAMP>, and <SAMP>`_'</SAMP>, in that order. +If <VAR>base</VAR> is less than or equal to 36, lowercase and uppercase +letters may be used interchangeably to represent numbers between 10 +and 35. +</P><P> + +Operators are evaluated in order of precedence. Sub-expressions in +parentheses are evaluated first and may override the precedence +rules above. +</P><P> + +<A NAME="Aliases"></A> +<HR SIZE="6"> +<A NAME="SEC84"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC83"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC85"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC85"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC68"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC91"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H2> 6.6 Aliases </H2> +<!--docid::SEC84::--> +<P> + +<VAR>Aliases</VAR> allow a string to be substituted for a word when it is used +as the first word of a simple command. +The shell maintains a list of aliases that may be set and unset with +the <CODE>alias</CODE> and <CODE>unalias</CODE> builtin commands. +</P><P> + +The first word of each simple command, if unquoted, is checked to see +if it has an alias. +If so, that word is replaced by the text of the alias. +The characters <SAMP>`/'</SAMP>, <SAMP>`$'</SAMP>, <SAMP>``'</SAMP>, <SAMP>`='</SAMP> and any of the +shell metacharacters or quoting characters listed above may not appear +in an alias name. +The replacement text may contain any valid +shell input, including shell metacharacters. +The first word of the replacement text is tested for +aliases, but a word that is identical to an alias being expanded +is not expanded a second time. +This means that one may alias <CODE>ls</CODE> to <CODE>"ls -F"</CODE>, +for instance, and Bash does not try to recursively expand the +replacement text. If the last character of the alias value is a +space or tab character, then the next command word following the +alias is also checked for alias expansion. +</P><P> + +Aliases are created and listed with the <CODE>alias</CODE> +command, and removed with the <CODE>unalias</CODE> command. +</P><P> + +There is no mechanism for using arguments in the replacement text, +as in <CODE>csh</CODE>. +If arguments are needed, a shell function should be used +(see section <A HREF="bashref.html#SEC24">3.3 Shell Functions</A>). +</P><P> + +Aliases are not expanded when the shell is not interactive, +unless the <CODE>expand_aliases</CODE> shell option is set using +<CODE>shopt</CODE> (see section <A HREF="bashref.html#SEC63">4.3.2 The Shopt Builtin</A>). +</P><P> + +The rules concerning the definition and use of aliases are +somewhat confusing. Bash +always reads at least one complete line +of input before executing any +of the commands on that line. Aliases are expanded when a +command is read, not when it is executed. Therefore, an +alias definition appearing on the same line as another +command does not take effect until the next line of input is read. +The commands following the alias definition +on that line are not affected by the new alias. +This behavior is also an issue when functions are executed. +Aliases are expanded when a function definition is read, +not when the function is executed, because a function definition +is itself a compound command. As a consequence, aliases +defined in a function are not available until after that +function is executed. To be safe, always put +alias definitions on a separate line, and do not use <CODE>alias</CODE> +in compound commands. +</P><P> + +For almost every purpose, shell functions are preferred over aliases. +</P><P> + +<A NAME="Arrays"></A> +<HR SIZE="6"> +<A NAME="SEC85"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC84"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC86"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC86"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC68"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC91"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H2> 6.7 Arrays </H2> +<!--docid::SEC85::--> +<P> + +Bash provides one-dimensional indexed and associative array variables. +Any variable may be used as an indexed array; +the <CODE>declare</CODE> builtin will explicitly declare an array. +There is no maximum +limit on the size of an array, nor any requirement that members +be indexed or assigned contiguously. +Indexed arrays are referenced using integers (including arithmetic +expressions (see section <A HREF="bashref.html#SEC83">6.5 Shell Arithmetic</A>) and are zero-based; +associative arrays use arbitrary strings. +</P><P> + +An indexed array is created automatically if any variable is assigned to +using the syntax +<TABLE><tr><td> </td><td class=example><pre>name[<VAR>subscript</VAR>]=<VAR>value</VAR> +</pre></td></tr></table></P><P> + +The <VAR>subscript</VAR> +is treated as an arithmetic expression that must evaluate to a number +greater than or equal to zero. To explicitly declare an array, use +<TABLE><tr><td> </td><td class=example><pre>declare -a <VAR>name</VAR> +</pre></td></tr></table>The syntax +<TABLE><tr><td> </td><td class=example><pre>declare -a <VAR>name</VAR>[<VAR>subscript</VAR>] +</pre></td></tr></table>is also accepted; the <VAR>subscript</VAR> is ignored. +</P><P> + +Associative arrays are created using +<TABLE><tr><td> </td><td class=example><pre>declare -A <VAR>name</VAR>. +</pre></td></tr></table></P><P> + +Attributes may be +specified for an array variable using the <CODE>declare</CODE> and +<CODE>readonly</CODE> builtins. Each attribute applies to all members of +an array. +</P><P> + +Arrays are assigned to using compound assignments of the form +<TABLE><tr><td> </td><td class=example><pre>name=(value<VAR>1</VAR> <small>...</small> value<VAR>n</VAR>) +</pre></td></tr></table>where each +<VAR>value</VAR> is of the form <CODE>[<VAR>subscript</VAR>]=</CODE><VAR>string</VAR>. +Indexed array assignments do not require the bracket and subscript. +When assigning to indexed arrays, if +the optional subscript is supplied, that index is assigned to; +otherwise the index of the element assigned is the last index assigned +to by the statement plus one. Indexing starts at zero. +</P><P> + +When assigning to an associative array, the subscript is required. +</P><P> + +This syntax is also accepted by the <CODE>declare</CODE> +builtin. Individual array elements may be assigned to using the +<CODE>name[</CODE><VAR>subscript</VAR><CODE>]=</CODE><VAR>value</VAR> syntax introduced above. +</P><P> + +Any element of an array may be referenced using +<CODE>${name[</CODE><VAR>subscript</VAR><CODE>]}</CODE>. +The braces are required to avoid +conflicts with the shell's filename expansion operators. If the +<VAR>subscript</VAR> is <SAMP>`@'</SAMP> or <SAMP>`*'</SAMP>, the word expands to all members +of the array <VAR>name</VAR>. These subscripts differ only when the word +appears within double quotes. +If the word is double-quoted, +<CODE>${name[*]}</CODE> expands to a single word with +the value of each array member separated by the first character of the +<CODE>IFS</CODE> variable, and <CODE>${name[@]}</CODE> expands each element of +<VAR>name</VAR> to a separate word. When there are no array members, +<CODE>${name[@]}</CODE> expands to nothing. +If the double-quoted expansion occurs within a word, the expansion of +the first parameter is joined with the beginning part of the original +word, and the expansion of the last parameter is joined with the last +part of the original word. +This is analogous to the +expansion of the special parameters <SAMP>`@'</SAMP> and <SAMP>`*'</SAMP>. +<CODE>${#name[</CODE><VAR>subscript</VAR><CODE>]}</CODE> expands to the length of +<CODE>${name[</CODE><VAR>subscript</VAR><CODE>]}</CODE>. +If <VAR>subscript</VAR> is <SAMP>`@'</SAMP> or +<SAMP>`*'</SAMP>, the expansion is the number of elements in the array. +Referencing an array variable without a subscript is equivalent to +referencing with a subscript of 0. +</P><P> + +An array variable is considered set if a subscript has been assigned a +value. The null string is a valid value. +</P><P> + +The <CODE>unset</CODE> builtin is used to destroy arrays. +<CODE>unset</CODE> <VAR>name</VAR>[<VAR>subscript</VAR>] +destroys the array element at index <VAR>subscript</VAR>. +Care must be taken to avoid unwanted side effects caused by filename +expansion. +<CODE>unset</CODE> <VAR>name</VAR>, where <VAR>name</VAR> is an array, removes the +entire array. A subscript of <SAMP>`*'</SAMP> or <SAMP>`@'</SAMP> also removes the +entire array. +</P><P> + +The <CODE>declare</CODE>, <CODE>local</CODE>, and <CODE>readonly</CODE> +builtins each accept a <SAMP>`-a'</SAMP> option to specify an indexed +array and a <SAMP>`-A'</SAMP> option to specify an associative array. +The <CODE>read</CODE> builtin accepts a <SAMP>`-a'</SAMP> +option to assign a list of words read from the standard input +to an array, and can read values from the standard input into +individual array elements. The <CODE>set</CODE> and <CODE>declare</CODE> +builtins display array values in a way that allows them to be +reused as input. +</P><P> + +<A NAME="The Directory Stack"></A> +<HR SIZE="6"> +<A NAME="SEC86"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC85"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC87"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC88"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC68"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC88"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H2> 6.8 The Directory Stack </H2> +<!--docid::SEC86::--> +<P> + +<BLOCKQUOTE><TABLE BORDER=0 CELLSPACING=0> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC87">6.8.1 Directory Stack Builtins</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Bash builtin commands to manipulate + the directory stack.</TD></TR> +</TABLE></BLOCKQUOTE> +<P> + +The directory stack is a list of recently-visited directories. The +<CODE>pushd</CODE> builtin adds directories to the stack as it changes +the current directory, and the <CODE>popd</CODE> builtin removes specified +directories from the stack and changes the current directory to +the directory removed. The <CODE>dirs</CODE> builtin displays the contents +of the directory stack. +</P><P> + +The contents of the directory stack are also visible +as the value of the <CODE>DIRSTACK</CODE> shell variable. +</P><P> + +<A NAME="Directory Stack Builtins"></A> +<HR SIZE="6"> +<A NAME="SEC87"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC86"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC88"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC88"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC86"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC88"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 6.8.1 Directory Stack Builtins </H3> +<!--docid::SEC87::--> +<P> + +<DL COMPACT> + +<DT><CODE>dirs</CODE> +<DD><A NAME="IDX290"></A> +<TABLE><tr><td> </td><td class=example><pre>dirs [+<VAR>N</VAR> | -<VAR>N</VAR>] [-clpv] +</pre></td></tr></table>Display the list of currently remembered directories. Directories +are added to the list with the <CODE>pushd</CODE> command; the +<CODE>popd</CODE> command removes directories from the list. +<DL COMPACT> +<DT><CODE>+<VAR>N</VAR></CODE> +<DD>Displays the <VAR>N</VAR>th directory (counting from the left of the +list printed by <CODE>dirs</CODE> when invoked without options), starting +with zero. +<DT><CODE>-<VAR>N</VAR></CODE> +<DD>Displays the <VAR>N</VAR>th directory (counting from the right of the +list printed by <CODE>dirs</CODE> when invoked without options), starting +with zero. +<DT><CODE>-c</CODE> +<DD>Clears the directory stack by deleting all of the elements. +<DT><CODE>-l</CODE> +<DD>Produces a longer listing; the default listing format uses a +tilde to denote the home directory. +<DT><CODE>-p</CODE> +<DD>Causes <CODE>dirs</CODE> to print the directory stack with one entry per +line. +<DT><CODE>-v</CODE> +<DD>Causes <CODE>dirs</CODE> to print the directory stack with one entry per +line, prefixing each entry with its index in the stack. +</DL> +<P> + +<DT><CODE>popd</CODE> +<DD><A NAME="IDX291"></A> +<TABLE><tr><td> </td><td class=example><pre>popd [+<VAR>N</VAR> | -<VAR>N</VAR>] [-n] +</pre></td></tr></table><P> + +Remove the top entry from the directory stack, and <CODE>cd</CODE> +to the new top directory. +When no arguments are given, <CODE>popd</CODE> +removes the top directory from the stack and +performs a <CODE>cd</CODE> to the new top directory. The +elements are numbered from 0 starting at the first directory listed with +<CODE>dirs</CODE>; i.e., <CODE>popd</CODE> is equivalent to <CODE>popd +0</CODE>. +<DL COMPACT> +<DT><CODE>+<VAR>N</VAR></CODE> +<DD>Removes the <VAR>N</VAR>th directory (counting from the left of the +list printed by <CODE>dirs</CODE>), starting with zero. +<DT><CODE>-<VAR>N</VAR></CODE> +<DD>Removes the <VAR>N</VAR>th directory (counting from the right of the +list printed by <CODE>dirs</CODE>), starting with zero. +<DT><CODE>-n</CODE> +<DD>Suppresses the normal change of directory when removing directories +from the stack, so that only the stack is manipulated. +</DL> +<P> + +<A NAME="IDX292"></A> +<DT><CODE>pushd</CODE> +<DD><TABLE><tr><td> </td><td class=example><pre>pushd [-n] [<VAR>+N</VAR> | <VAR>-N</VAR> | <VAR>dir</VAR> ] +</pre></td></tr></table><P> + +Save the current directory on the top of the directory stack +and then <CODE>cd</CODE> to <VAR>dir</VAR>. +With no arguments, <CODE>pushd</CODE> exchanges the top two directories. +</P><P> + +<DL COMPACT> +<DT><CODE>-n</CODE> +<DD>Suppresses the normal change of directory when adding directories +to the stack, so that only the stack is manipulated. +<DT><CODE>+<VAR>N</VAR></CODE> +<DD>Brings the <VAR>N</VAR>th directory (counting from the left of the +list printed by <CODE>dirs</CODE>, starting with zero) to the top of +the list by rotating the stack. +<DT><CODE>-<VAR>N</VAR></CODE> +<DD>Brings the <VAR>N</VAR>th directory (counting from the right of the +list printed by <CODE>dirs</CODE>, starting with zero) to the top of +the list by rotating the stack. +<DT><CODE><VAR>dir</VAR></CODE> +<DD>Makes the current working directory be the top of the stack, and then +executes the equivalent of `<CODE>cd</CODE> <VAR>dir</VAR>'. +<CODE>cd</CODE>s to <VAR>dir</VAR>. +</DL> +<P> + +</DL> +<P> + +<A NAME="Printing a Prompt"></A> +<HR SIZE="6"> +<A NAME="SEC88"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC87"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC89"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC68"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC68"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC91"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H2> 6.9 Controlling the Prompt </H2> +<!--docid::SEC88::--> +<P> + +The value of the variable <CODE>PROMPT_COMMAND</CODE> is examined just before +Bash prints each primary prompt. If <CODE>PROMPT_COMMAND</CODE> is set and +has a non-null value, then the +value is executed just as if it had been typed on the command line. +</P><P> + +In addition, the following table describes the special characters which +can appear in the prompt variables: +</P><P> + +<DL COMPACT> +<DT><CODE>\a</CODE> +<DD>A bell character. +<DT><CODE>\d</CODE> +<DD>The date, in "Weekday Month Date" format (e.g., "Tue May 26"). +<DT><CODE>\D{<VAR>format</VAR>}</CODE> +<DD>The <VAR>format</VAR> is passed to <CODE>strftime</CODE>(3) and the result is inserted +into the prompt string; an empty <VAR>format</VAR> results in a locale-specific +time representation. The braces are required. +<DT><CODE>\e</CODE> +<DD>An escape character. +<DT><CODE>\h</CODE> +<DD>The hostname, up to the first `.'. +<DT><CODE>\H</CODE> +<DD>The hostname. +<DT><CODE>\j</CODE> +<DD>The number of jobs currently managed by the shell. +<DT><CODE>\l</CODE> +<DD>The basename of the shell's terminal device name. +<DT><CODE>\n</CODE> +<DD>A newline. +<DT><CODE>\r</CODE> +<DD>A carriage return. +<DT><CODE>\s</CODE> +<DD>The name of the shell, the basename of <CODE>$0</CODE> (the portion +following the final slash). +<DT><CODE>\t</CODE> +<DD>The time, in 24-hour HH:MM:SS format. +<DT><CODE>\T</CODE> +<DD>The time, in 12-hour HH:MM:SS format. +<DT><CODE>\@</CODE> +<DD>The time, in 12-hour am/pm format. +<DT><CODE>\A</CODE> +<DD>The time, in 24-hour HH:MM format. +<DT><CODE>\u</CODE> +<DD>The username of the current user. +<DT><CODE>\v</CODE> +<DD>The version of Bash (e.g., 2.00) +<DT><CODE>\V</CODE> +<DD>The release of Bash, version + patchlevel (e.g., 2.00.0) +<DT><CODE>\w</CODE> +<DD>The current working directory, with <CODE>$HOME</CODE> abbreviated with a tilde +(uses the <CODE>$PROMPT_DIRTRIM</CODE> variable). +<DT><CODE>\W</CODE> +<DD>The basename of <CODE>$PWD</CODE>, with <CODE>$HOME</CODE> abbreviated with a tilde. +<DT><CODE>\!</CODE> +<DD>The history number of this command. +<DT><CODE>\#</CODE> +<DD>The command number of this command. +<DT><CODE>\$</CODE> +<DD>If the effective uid is 0, <CODE>#</CODE>, otherwise <CODE>$</CODE>. +<DT><CODE>\<VAR>nnn</VAR></CODE> +<DD>The character whose ASCII code is the octal value <VAR>nnn</VAR>. +<DT><CODE>\\</CODE> +<DD>A backslash. +<DT><CODE>\[</CODE> +<DD>Begin a sequence of non-printing characters. This could be used to +embed a terminal control sequence into the prompt. +<DT><CODE>\]</CODE> +<DD>End a sequence of non-printing characters. +</DL> +<P> + +The command number and the history number are usually different: +the history number of a command is its position in the history +list, which may include commands restored from the history file +(see section <A HREF="bashref.html#SEC120">9.1 Bash History Facilities</A>), while the command number is +the position in the sequence of commands executed during the current +shell session. +</P><P> + +After the string is decoded, it is expanded via +parameter expansion, command substitution, arithmetic +expansion, and quote removal, subject to the value of the +<CODE>promptvars</CODE> shell option (see section <A HREF="bashref.html#SEC60">4.2 Bash Builtin Commands</A>). +</P><P> + +<A NAME="The Restricted Shell"></A> +<HR SIZE="6"> +<A NAME="SEC89"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC88"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC90"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC70"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC68"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC91"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H2> 6.10 The Restricted Shell </H2> +<!--docid::SEC89::--> +<P> + +If Bash is started with the name <CODE>rbash</CODE>, or the +<SAMP>`--restricted'</SAMP> +or +<SAMP>`-r'</SAMP> +option is supplied at invocation, the shell becomes restricted. +A restricted shell is used to +set up an environment more controlled than the standard shell. +A restricted shell behaves identically to <CODE>bash</CODE> +with the exception that the following are disallowed or not performed: +</P><P> + +<UL> +<LI> +Changing directories with the <CODE>cd</CODE> builtin. +<LI> +Setting or unsetting the values of the <CODE>SHELL</CODE>, <CODE>PATH</CODE>, +<CODE>ENV</CODE>, or <CODE>BASH_ENV</CODE> variables. +<LI> +Specifying command names containing slashes. +<LI> +Specifying a filename containing a slash as an argument to the <CODE>.</CODE> +builtin command. +<LI> +Specifying a filename containing a slash as an argument to the <SAMP>`-p'</SAMP> +option to the <CODE>hash</CODE> builtin command. +<LI> +Importing function definitions from the shell environment at startup. +<LI> +Parsing the value of <CODE>SHELLOPTS</CODE> from the shell environment at startup. +<LI> +Redirecting output using the <SAMP>`>'</SAMP>, <SAMP>`>|'</SAMP>, <SAMP>`<>'</SAMP>, <SAMP>`>&'</SAMP>, +<SAMP>`&>'</SAMP>, and <SAMP>`>>'</SAMP> redirection operators. +<LI> +Using the <CODE>exec</CODE> builtin to replace the shell with another command. +<LI> +Adding or deleting builtin commands with the +<SAMP>`-f'</SAMP> and <SAMP>`-d'</SAMP> options to the <CODE>enable</CODE> builtin. +<LI> +Using the <CODE>enable</CODE> builtin command to enable disabled shell builtins. +<LI> +Specifying the <SAMP>`-p'</SAMP> option to the <CODE>command</CODE> builtin. +<LI> +Turning off restricted mode with <SAMP>`set +r'</SAMP> or <SAMP>`set +o restricted'</SAMP>. +</UL> +<P> + +These restrictions are enforced after any startup files are read. +</P><P> + +When a command that is found to be a shell script is executed +(see section <A HREF="bashref.html#SEC57">3.8 Shell Scripts</A>), <CODE>rbash</CODE> turns off any restrictions in +the shell spawned to execute the script. +</P><P> + +<A NAME="Bash POSIX Mode"></A> +<HR SIZE="6"> +<A NAME="SEC90"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC89"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC91"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC70"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC68"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC91"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H2> 6.11 Bash POSIX Mode </H2> +<!--docid::SEC90::--> +<P> + +Starting Bash with the <SAMP>`--posix'</SAMP> command-line option or executing +<SAMP>`set -o posix'</SAMP> while Bash is running will cause Bash to conform more +closely to the POSIX standard by changing the behavior to +match that specified by POSIX in areas where the Bash default differs. +</P><P> + +When invoked as <CODE>sh</CODE>, Bash enters POSIX mode after reading the +startup files. +</P><P> + +The following list is what's changed when `POSIX mode' is in effect: +</P><P> + +<OL> +<LI> +When a command in the hash table no longer exists, Bash will re-search +<CODE>$PATH</CODE> to find the new location. This is also available with +<SAMP>`shopt -s checkhash'</SAMP>. +<P> + +<LI> +The message printed by the job control code and builtins when a job +exits with a non-zero status is `Done(status)'. +<P> + +<LI> +The message printed by the job control code and builtins when a job +is stopped is `Stopped(<VAR>signame</VAR>)', where <VAR>signame</VAR> is, for +example, <CODE>SIGTSTP</CODE>. +<P> + +<LI> +The <CODE>bg</CODE> builtin uses the required format to describe each job placed +in the background, which does not include an indication of whether the job +is the current or previous job. +<P> + +<LI> +Reserved words appearing in a context where reserved words are recognized +do not undergo alias expansion. +<P> + +<LI> +The POSIX <CODE>PS1</CODE> and <CODE>PS2</CODE> expansions of <SAMP>`!'</SAMP> to +the history number and <SAMP>`!!'</SAMP> to <SAMP>`!'</SAMP> are enabled, +and parameter expansion is performed on the values of <CODE>PS1</CODE> and +<CODE>PS2</CODE> regardless of the setting of the <CODE>promptvars</CODE> option. +<P> + +<LI> +The POSIX startup files are executed (<CODE>$ENV</CODE>) rather than +the normal Bash files. +<P> + +<LI> +Tilde expansion is only performed on assignments preceding a command +name, rather than on all assignment statements on the line. +<P> + +<LI> +The default history file is <TT>`~/.sh_history'</TT> (this is the +default value of <CODE>$HISTFILE</CODE>). +<P> + +<LI> +The output of <SAMP>`kill -l'</SAMP> prints all the signal names on a single line, +separated by spaces, without the <SAMP>`SIG'</SAMP> prefix. +<P> + +<LI> +The <CODE>kill</CODE> builtin does not accept signal names with a <SAMP>`SIG'</SAMP> +prefix. +<P> + +<LI> +Non-interactive shells exit if <VAR>filename</VAR> in <CODE>.</CODE> <VAR>filename</VAR> +is not found. +<P> + +<LI> +Non-interactive shells exit if a syntax error in an arithmetic expansion +results in an invalid expression. +<P> + +<LI> +Redirection operators do not perform filename expansion on the word +in the redirection unless the shell is interactive. +<P> + +<LI> +Redirection operators do not perform word splitting on the word in the +redirection. +<P> + +<LI> +Function names must be valid shell <CODE>name</CODE>s. That is, they may not +contain characters other than letters, digits, and underscores, and +may not start with a digit. Declaring a function with an invalid name +causes a fatal syntax error in non-interactive shells. +<P> + +<LI> +POSIX special builtins are found before shell functions +during command lookup. +<P> + +<LI> +If a POSIX special builtin returns an error status, a +non-interactive shell exits. The fatal errors are those listed in +the POSIX standard, and include things like passing incorrect options, +redirection errors, variable assignment errors for assignments preceding +the command name, and so on. +<P> + +<LI> +If <CODE>CDPATH</CODE> is set, the <CODE>cd</CODE> builtin will not implicitly +append the current directory to it. This means that <CODE>cd</CODE> will +fail if no valid directory name can be constructed from +any of the entries in <CODE>$CDPATH</CODE>, even if the a directory with +the same name as the name given as an argument to <CODE>cd</CODE> exists +in the current directory. +<P> + +<LI> +A non-interactive shell exits with an error status if a variable +assignment error occurs when no command name follows the assignment +statements. +A variable assignment error occurs, for example, when trying to assign +a value to a readonly variable. +<P> + +<LI> +A non-interactive shell exits with an error status if the iteration +variable in a <CODE>for</CODE> statement or the selection variable in a +<CODE>select</CODE> statement is a readonly variable. +<P> + +<LI> +Process substitution is not available. +<P> + +<LI> +Assignment statements preceding POSIX special builtins +persist in the shell environment after the builtin completes. +<P> + +<LI> +Assignment statements preceding shell function calls persist in the +shell environment after the function returns, as if a POSIX +special builtin command had been executed. +<P> + +<LI> +The <CODE>export</CODE> and <CODE>readonly</CODE> builtin commands display their +output in the format required by POSIX. +<P> + +<LI> +The <CODE>trap</CODE> builtin displays signal names without the leading +<CODE>SIG</CODE>. +<P> + +<LI> +The <CODE>trap</CODE> builtin doesn't check the first argument for a possible +signal specification and revert the signal handling to the original +disposition if it is, unless that argument consists solely of digits and +is a valid signal number. If users want to reset the handler for a given +signal to the original disposition, they should use <SAMP>`-'</SAMP> as the +first argument. +<P> + +<LI> +The <CODE>.</CODE> and <CODE>source</CODE> builtins do not search the current directory +for the filename argument if it is not found by searching <CODE>PATH</CODE>. +<P> + +<LI> +Subshells spawned to execute command substitutions inherit the value of +the <SAMP>`-e'</SAMP> option from the parent shell. When not in POSIX mode, +Bash clears the <SAMP>`-e'</SAMP> option in such subshells. +<P> + +<LI> +Alias expansion is always enabled, even in non-interactive shells. +<P> + +<LI> +When the <CODE>alias</CODE> builtin displays alias definitions, it does not +display them with a leading <SAMP>`alias '</SAMP> unless the <SAMP>`-p'</SAMP> option +is supplied. +<P> + +<LI> +When the <CODE>set</CODE> builtin is invoked without options, it does not display +shell function names and definitions. +<P> + +<LI> +When the <CODE>set</CODE> builtin is invoked without options, it displays +variable values without quotes, unless they contain shell metacharacters, +even if the result contains nonprinting characters. +<P> + +<LI> +When the <CODE>cd</CODE> builtin is invoked in <VAR>logical</VAR> mode, and the pathname +constructed from <CODE>$PWD</CODE> and the directory name supplied as an argument +does not refer to an existing directory, <CODE>cd</CODE> will fail instead of +falling back to <VAR>physical</VAR> mode. +<P> + +<LI> +When the <CODE>pwd</CODE> builtin is supplied the <SAMP>`-P'</SAMP> option, it resets +<CODE>$PWD</CODE> to a pathname containing no symlinks. +<P> + +<LI> +The <CODE>pwd</CODE> builtin verifies that the value it prints is the same as the +current directory, even if it is not asked to check the file system with the +<SAMP>`-P'</SAMP> option. +<P> + +<LI> +When listing the history, the <CODE>fc</CODE> builtin does not include an +indication of whether or not a history entry has been modified. +<P> + +<LI> +The default editor used by <CODE>fc</CODE> is <CODE>ed</CODE>. +<P> + +<LI> +The <CODE>type</CODE> and <CODE>command</CODE> builtins will not report a non-executable +file as having been found, though the shell will attempt to execute such a +file if it is the only so-named file found in <CODE>$PATH</CODE>. +<P> + +<LI> +The <CODE>vi</CODE> editing mode will invoke the <CODE>vi</CODE> editor directly when +the <SAMP>`v'</SAMP> command is run, instead of checking <CODE>$VISUAL</CODE> and +<CODE>$EDITOR</CODE>. +<P> + +<LI> +When the <CODE>xpg_echo</CODE> option is enabled, Bash does not attempt to interpret +any arguments to <CODE>echo</CODE> as options. Each argument is displayed, after +escape characters are converted. +<P> + +<LI> +The <CODE>ulimit</CODE> builtin uses a block size of 512 bytes for the <SAMP>`-c'</SAMP> +and <SAMP>`-f'</SAMP> options. +<P> + +<LI> +The arrival of <CODE>SIGCHLD</CODE> when a trap is set on <CODE>SIGCHLD</CODE> does +not interrupt the <CODE>wait</CODE> builtin and cause it to return immediately. +The trap command is run once for each child that exits. +<P> + +</OL> +<P> + +There is other POSIX behavior that Bash does not implement by +default even when in POSIX mode. +Specifically: +</P><P> + +<OL> + +<LI> +The <CODE>fc</CODE> builtin checks <CODE>$EDITOR</CODE> as a program to edit history +entries if <CODE>FCEDIT</CODE> is unset, rather than defaulting directly to +<CODE>ed</CODE>. <CODE>fc</CODE> uses <CODE>ed</CODE> if <CODE>EDITOR</CODE> is unset. +<P> + +<LI> +As noted above, Bash requires the <CODE>xpg_echo</CODE> option to be enabled for +the <CODE>echo</CODE> builtin to be fully conformant. +<P> + +</OL> +<P> + +Bash can be configured to be POSIX-conformant by default, by specifying +the <SAMP>`--enable-strict-posix-default'</SAMP> to <CODE>configure</CODE> when building +(see section <A HREF="bashref.html#SEC134">10.8 Optional Features</A>). +</P><P> + +<A NAME="Job Control"></A> +<HR SIZE="6"> +<A NAME="SEC91"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC90"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC92"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC95"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC95"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H1> 7. Job Control </H1> +<!--docid::SEC91::--> +<P> + +This chapter discusses what job control is, how it works, and how +Bash allows you to access its facilities. +</P><P> + +<BLOCKQUOTE><TABLE BORDER=0 CELLSPACING=0> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC92">7.1 Job Control Basics</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">How job control works.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC93">7.2 Job Control Builtins</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Bash builtin commands used to interact + with job control.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC94">7.3 Job Control Variables</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Variables Bash uses to customize job + control.</TD></TR> +</TABLE></BLOCKQUOTE> +<P> + +<A NAME="Job Control Basics"></A> +<HR SIZE="6"> +<A NAME="SEC92"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC91"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC93"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC91"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC91"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC95"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H2> 7.1 Job Control Basics </H2> +<!--docid::SEC92::--> +<P> + +Job control +refers to the ability to selectively stop (suspend) +the execution of processes and continue (resume) +their execution at a later point. A user typically employs +this facility via an interactive interface supplied jointly +by the operating system kernel's terminal driver and Bash. +</P><P> + +The shell associates a <VAR>job</VAR> with each pipeline. It keeps a +table of currently executing jobs, which may be listed with the +<CODE>jobs</CODE> command. When Bash starts a job +asynchronously, it prints a line that looks +like: +<TABLE><tr><td> </td><td class=example><pre>[1] 25647 +</pre></td></tr></table>indicating that this job is job number 1 and that the process ID +of the last process in the pipeline associated with this job is +25647. All of the processes in a single pipeline are members of +the same job. Bash uses the <VAR>job</VAR> abstraction as the +basis for job control. +</P><P> + +To facilitate the implementation of the user interface to job +control, the operating system maintains the notion of a current terminal +process group ID. Members of this process group (processes whose +process group ID is equal to the current terminal process group +ID) receive keyboard-generated signals such as <CODE>SIGINT</CODE>. +These processes are said to be in the foreground. Background +processes are those whose process group ID differs from the +terminal's; such processes are immune to keyboard-generated +signals. Only foreground processes are allowed to read from or, if +the user so specifies with <CODE>stty tostop</CODE>, write to the terminal. +Background processes which attempt to +read from (write to when <CODE>stty tostop</CODE> is in effect) the +terminal are sent a <CODE>SIGTTIN</CODE> (<CODE>SIGTTOU</CODE>) +signal by the kernel's terminal driver, +which, unless caught, suspends the process. +</P><P> + +If the operating system on which Bash is running supports +job control, Bash contains facilities to use it. Typing the +<VAR>suspend</VAR> character (typically <SAMP>`^Z'</SAMP>, Control-Z) while a +process is running causes that process to be stopped and returns +control to Bash. Typing the <VAR>delayed suspend</VAR> character +(typically <SAMP>`^Y'</SAMP>, Control-Y) causes the process to be stopped +when it attempts to read input from the terminal, and control to +be returned to Bash. The user then manipulates the state of +this job, using the <CODE>bg</CODE> command to continue it in the +background, the <CODE>fg</CODE> command to continue it in the +foreground, or the <CODE>kill</CODE> command to kill it. A <SAMP>`^Z'</SAMP> +takes effect immediately, and has the additional side effect of +causing pending output and typeahead to be discarded. +</P><P> + +There are a number of ways to refer to a job in the shell. The +character <SAMP>`%'</SAMP> introduces a job specification (<VAR>jobspec</VAR>). +</P><P> + +Job number <CODE>n</CODE> may be referred to as <SAMP>`%n'</SAMP>. +The symbols <SAMP>`%%'</SAMP> and <SAMP>`%+'</SAMP> refer to the shell's notion of the +current job, which is the last job stopped while it was in the foreground +or started in the background. +A single <SAMP>`%'</SAMP> (with no accompanying job specification) also refers +to the current job. +The previous job may be referenced using <SAMP>`%-'</SAMP>. +If there is only a single job, <SAMP>`%+'</SAMP> and <SAMP>`%-'</SAMP> can both be used +to refer to that job. +In output pertaining to jobs (e.g., the output of the <CODE>jobs</CODE> +command), the current job is always flagged with a <SAMP>`+'</SAMP>, and the +previous job with a <SAMP>`-'</SAMP>. +</P><P> + +A job may also be referred to +using a prefix of the name used to start it, or using a substring +that appears in its command line. For example, <SAMP>`%ce'</SAMP> refers +to a stopped <CODE>ce</CODE> job. Using <SAMP>`%?ce'</SAMP>, on the +other hand, refers to any job containing the string <SAMP>`ce'</SAMP> in +its command line. If the prefix or substring matches more than one job, +Bash reports an error. +</P><P> + +Simply naming a job can be used to bring it into the foreground: +<SAMP>`%1'</SAMP> is a synonym for <SAMP>`fg %1'</SAMP>, bringing job 1 from the +background into the foreground. Similarly, <SAMP>`%1 &'</SAMP> resumes +job 1 in the background, equivalent to <SAMP>`bg %1'</SAMP> +</P><P> + +The shell learns immediately whenever a job changes state. +Normally, Bash waits until it is about to print a prompt +before reporting changes in a job's status so as to not interrupt +any other output. +If the <SAMP>`-b'</SAMP> option to the <CODE>set</CODE> builtin is enabled, +Bash reports such changes immediately (see section <A HREF="bashref.html#SEC62">4.3.1 The Set Builtin</A>). +Any trap on <CODE>SIGCHLD</CODE> is executed for each child process +that exits. +</P><P> + +If an attempt to exit Bash is made while jobs are stopped, (or running, if +the <CODE>checkjobs</CODE> option is enabled -- see <A HREF="bashref.html#SEC63">4.3.2 The Shopt Builtin</A>), the +shell prints a warning message, and if the <CODE>checkjobs</CODE> option is +enabled, lists the jobs and their statuses. +The <CODE>jobs</CODE> command may then be used to inspect their status. +If a second attempt to exit is made without an intervening command, +Bash does not print another warning, and any stopped jobs are terminated. +</P><P> + +<A NAME="Job Control Builtins"></A> +<HR SIZE="6"> +<A NAME="SEC93"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC92"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC94"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC94"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC91"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC95"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H2> 7.2 Job Control Builtins </H2> +<!--docid::SEC93::--> +<P> + +<DL COMPACT> + +<DT><CODE>bg</CODE> +<DD><A NAME="IDX293"></A> +<TABLE><tr><td> </td><td class=example><pre>bg [<VAR>jobspec</VAR> <small>...</small>] +</pre></td></tr></table>Resume each suspended job <VAR>jobspec</VAR> in the background, as if it +had been started with <SAMP>`&'</SAMP>. +If <VAR>jobspec</VAR> is not supplied, the current job is used. +The return status is zero unless it is run when job control is not +enabled, or, when run with job control enabled, any +<VAR>jobspec</VAR> was not found or specifies a job +that was started without job control. +<P> + +<DT><CODE>fg</CODE> +<DD><A NAME="IDX294"></A> +<TABLE><tr><td> </td><td class=example><pre>fg [<VAR>jobspec</VAR>] +</pre></td></tr></table>Resume the job <VAR>jobspec</VAR> in the foreground and make it the current job. +If <VAR>jobspec</VAR> is not supplied, the current job is used. +The return status is that of the command placed into the foreground, +or non-zero if run when job control is disabled or, when run with +job control enabled, <VAR>jobspec</VAR> does not specify a valid job or +<VAR>jobspec</VAR> specifies a job that was started without job control. +<P> + +<DT><CODE>jobs</CODE> +<DD><A NAME="IDX295"></A> +<TABLE><tr><td> </td><td class=example><pre>jobs [-lnprs] [<VAR>jobspec</VAR>] +jobs -x <VAR>command</VAR> [<VAR>arguments</VAR>] +</pre></td></tr></table><P> + +The first form lists the active jobs. The options have the +following meanings: +</P><P> + +<DL COMPACT> +<DT><CODE>-l</CODE> +<DD>List process IDs in addition to the normal information. +<P> + +<DT><CODE>-n</CODE> +<DD>Display information only about jobs that have changed status since +the user was last notified of their status. +<P> + +<DT><CODE>-p</CODE> +<DD>List only the process ID of the job's process group leader. +<P> + +<DT><CODE>-r</CODE> +<DD>Restrict output to running jobs. +<P> + +<DT><CODE>-s</CODE> +<DD>Restrict output to stopped jobs. +</DL> +<P> + +If <VAR>jobspec</VAR> is given, +output is restricted to information about that job. +If <VAR>jobspec</VAR> is not supplied, the status of all jobs is +listed. +</P><P> + +If the <SAMP>`-x'</SAMP> option is supplied, <CODE>jobs</CODE> replaces any +<VAR>jobspec</VAR> found in <VAR>command</VAR> or <VAR>arguments</VAR> with the +corresponding process group ID, and executes <VAR>command</VAR>, +passing it <VAR>argument</VAR>s, returning its exit status. +</P><P> + +<DT><CODE>kill</CODE> +<DD><A NAME="IDX296"></A> +<TABLE><tr><td> </td><td class=example><pre>kill [-s <VAR>sigspec</VAR>] [-n <VAR>signum</VAR>] [-<VAR>sigspec</VAR>] <VAR>jobspec</VAR> or <VAR>pid</VAR> +kill -l [<VAR>exit_status</VAR>] +</pre></td></tr></table>Send a signal specified by <VAR>sigspec</VAR> or <VAR>signum</VAR> to the process +named by job specification <VAR>jobspec</VAR> or process ID <VAR>pid</VAR>. +<VAR>sigspec</VAR> is either a case-insensitive signal name such as +<CODE>SIGINT</CODE> (with or without the <CODE>SIG</CODE> prefix) +or a signal number; <VAR>signum</VAR> is a signal number. +If <VAR>sigspec</VAR> and <VAR>signum</VAR> are not present, <CODE>SIGTERM</CODE> is used. +The <SAMP>`-l'</SAMP> option lists the signal names. +If any arguments are supplied when <SAMP>`-l'</SAMP> is given, the names of the +signals corresponding to the arguments are listed, and the return status +is zero. +<VAR>exit_status</VAR> is a number specifying a signal number or the exit +status of a process terminated by a signal. +The return status is zero if at least one signal was successfully sent, +or non-zero if an error occurs or an invalid option is encountered. +<P> + +<DT><CODE>wait</CODE> +<DD><A NAME="IDX297"></A> +<TABLE><tr><td> </td><td class=example><pre>wait [<VAR>jobspec</VAR> or <VAR>pid</VAR> ...] +</pre></td></tr></table>Wait until the child process specified by each process ID <VAR>pid</VAR> +or job specification <VAR>jobspec</VAR> exits and return the exit status of the +last command waited for. +If a job spec is given, all processes in the job are waited for. +If no arguments are given, all currently active child processes are +waited for, and the return status is zero. +If neither <VAR>jobspec</VAR> nor <VAR>pid</VAR> specifies an active child process +of the shell, the return status is 127. +<P> + +<DT><CODE>disown</CODE> +<DD><A NAME="IDX298"></A> +<TABLE><tr><td> </td><td class=example><pre>disown [-ar] [-h] [<VAR>jobspec</VAR> <small>...</small>] +</pre></td></tr></table>Without options, each <VAR>jobspec</VAR> is removed from the table of +active jobs. +If the <SAMP>`-h'</SAMP> option is given, the job is not removed from the table, +but is marked so that <CODE>SIGHUP</CODE> is not sent to the job if the shell +receives a <CODE>SIGHUP</CODE>. +If <VAR>jobspec</VAR> is not present, and neither the <SAMP>`-a'</SAMP> nor <SAMP>`-r'</SAMP> +option is supplied, the current job is used. +If no <VAR>jobspec</VAR> is supplied, the <SAMP>`-a'</SAMP> option means to remove or +mark all jobs; the <SAMP>`-r'</SAMP> option without a <VAR>jobspec</VAR> +argument restricts operation to running jobs. +<P> + +<DT><CODE>suspend</CODE> +<DD><A NAME="IDX299"></A> +<TABLE><tr><td> </td><td class=example><pre>suspend [-f] +</pre></td></tr></table>Suspend the execution of this shell until it receives a +<CODE>SIGCONT</CODE> signal. +A login shell cannot be suspended; the <SAMP>`-f'</SAMP> +option can be used to override this and force the suspension. +<P> + +</DL> +<P> + +When job control is not active, the <CODE>kill</CODE> and <CODE>wait</CODE> +builtins do not accept <VAR>jobspec</VAR> arguments. They must be +supplied process IDs. +</P><P> + +<A NAME="Job Control Variables"></A> +<HR SIZE="6"> +<A NAME="SEC94"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC93"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC95"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC91"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC91"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC95"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H2> 7.3 Job Control Variables </H2> +<!--docid::SEC94::--> +<P> + +<DL COMPACT> + +<A NAME="IDX300"></A> +<DT><CODE>auto_resume</CODE> +<DD><A NAME="IDX301"></A> +This variable controls how the shell interacts with the user and +job control. If this variable exists then single word simple +commands without redirections are treated as candidates for resumption +of an existing job. There is no ambiguity allowed; if there is +more than one job beginning with the string typed, then +the most recently accessed job will be selected. +The name of a stopped job, in this context, is the command line +used to start it. If this variable is set to the value <SAMP>`exact'</SAMP>, +the string supplied must match the name of a stopped job exactly; +if set to <SAMP>`substring'</SAMP>, +the string supplied needs to match a substring of the name of a +stopped job. The <SAMP>`substring'</SAMP> value provides functionality +analogous to the <SAMP>`%?'</SAMP> job ID (see section <A HREF="bashref.html#SEC92">7.1 Job Control Basics</A>). +If set to any other value, the supplied string must +be a prefix of a stopped job's name; this provides functionality +analogous to the <SAMP>`%'</SAMP> job ID. +<P> + +</DL> +<P> + +<A NAME="IDX302"></A> +</P><P> + +<A NAME="Command Line Editing"></A> +<HR SIZE="6"> +<A NAME="SEC95"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC94"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC96"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC119"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC119"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H1> 8. Command Line Editing </H1> +<!--docid::SEC95::--> +<P> + +This chapter describes the basic features of the GNU +command line editing interface. +Command line editing is provided by the Readline library, which is +used by several different programs, including Bash. +Command line editing is enabled by default when using an interactive shell, +unless the <SAMP>`--noediting'</SAMP> option is supplied at shell invocation. +Line editing is also used when using the <SAMP>`-e'</SAMP> option to the +<CODE>read</CODE> builtin command (see section <A HREF="bashref.html#SEC60">4.2 Bash Builtin Commands</A>). +By default, the line editing commands are similar to those of emacs. +A vi-style line editing interface is also available. +Line editing can be enabled at any time using the <SAMP>`-o emacs'</SAMP> or +<SAMP>`-o vi'</SAMP> options to the <CODE>set</CODE> builtin command +(see section <A HREF="bashref.html#SEC62">4.3.1 The Set Builtin</A>), or disabled using the <SAMP>`+o emacs'</SAMP> or +<SAMP>`+o vi'</SAMP> options to <CODE>set</CODE>. +</P><P> + +<BLOCKQUOTE><TABLE BORDER=0 CELLSPACING=0> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC96">8.1 Introduction to Line Editing</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Notation used in this text.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC97">8.2 Readline Interaction</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">The minimum set of commands for editing a line.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC103">8.3 Readline Init File</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Customizing Readline from a user's view.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC107">8.4 Bindable Readline Commands</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">A description of most of the Readline commands + available for binding</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC116">8.5 Readline vi Mode</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">A short description of how to make Readline + behave like the vi editor.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC117">8.6 Programmable Completion</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">How to specify the possible completions for + a specific command.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC118">8.7 Programmable Completion Builtins</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Builtin commands to specify how to + complete arguments for a particular command.</TD></TR> +</TABLE></BLOCKQUOTE> +<P> + +<A NAME="Introduction and Notation"></A> +<HR SIZE="6"> +<A NAME="SEC96"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC95"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC97"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC95"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC95"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC119"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H2> 8.1 Introduction to Line Editing </H2> +<!--docid::SEC96::--> +<P> + +The following paragraphs describe the notation used to represent +keystrokes. +</P><P> + +The text <KBD>C-k</KBD> is read as `Control-K' and describes the character +produced when the <KBD>k</KBD> key is pressed while the Control key +is depressed. +</P><P> + +The text <KBD>M-k</KBD> is read as `Meta-K' and describes the character +produced when the Meta key (if you have one) is depressed, and the <KBD>k</KBD> +key is pressed. +The Meta key is labeled <KBD>ALT</KBD> on many keyboards. +On keyboards with two keys labeled <KBD>ALT</KBD> (usually to either side of +the space bar), the <KBD>ALT</KBD> on the left side is generally set to +work as a Meta key. +The <KBD>ALT</KBD> key on the right may also be configured to work as a +Meta key or may be configured as some other modifier, such as a +Compose key for typing accented characters. +</P><P> + +If you do not have a Meta or <KBD>ALT</KBD> key, or another key working as +a Meta key, the identical keystroke can be generated by typing <KBD>ESC</KBD> +<EM>first</EM>, and then typing <KBD>k</KBD>. +Either process is known as <EM>metafying</EM> the <KBD>k</KBD> key. +</P><P> + +The text <KBD>M-C-k</KBD> is read as `Meta-Control-k' and describes the +character produced by <EM>metafying</EM> <KBD>C-k</KBD>. +</P><P> + +In addition, several keys have their own names. Specifically, +<KBD>DEL</KBD>, <KBD>ESC</KBD>, <KBD>LFD</KBD>, <KBD>SPC</KBD>, <KBD>RET</KBD>, and <KBD>TAB</KBD> all +stand for themselves when seen in this text, or in an init file +(see section <A HREF="bashref.html#SEC103">8.3 Readline Init File</A>). +If your keyboard lacks a <KBD>LFD</KBD> key, typing <KBD>C-j</KBD> will +produce the desired character. +The <KBD>RET</KBD> key may be labeled <KBD>Return</KBD> or <KBD>Enter</KBD> on +some keyboards. +</P><P> + +<A NAME="Readline Interaction"></A> +<HR SIZE="6"> +<A NAME="SEC97"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC96"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC98"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC103"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC95"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC103"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H2> 8.2 Readline Interaction </H2> +<!--docid::SEC97::--> +<P> + +Often during an interactive session you type in a long line of text, +only to notice that the first word on the line is misspelled. The +Readline library gives you a set of commands for manipulating the text +as you type it in, allowing you to just fix your typo, and not forcing +you to retype the majority of the line. Using these editing commands, +you move the cursor to the place that needs correction, and delete or +insert the text of the corrections. Then, when you are satisfied with +the line, you simply press <KBD>RET</KBD>. You do not have to be at the +end of the line to press <KBD>RET</KBD>; the entire line is accepted +regardless of the location of the cursor within the line. +</P><P> + +<BLOCKQUOTE><TABLE BORDER=0 CELLSPACING=0> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC98">8.2.1 Readline Bare Essentials</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">The least you need to know about Readline.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC99">8.2.2 Readline Movement Commands</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Moving about the input line.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC100">8.2.3 Readline Killing Commands</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">How to delete text, and how to get it back!</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC101">8.2.4 Readline Arguments</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Giving numeric arguments to commands.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC102">8.2.5 Searching for Commands in the History</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Searching through previous lines.</TD></TR> +</TABLE></BLOCKQUOTE> +<P> + +<A NAME="Readline Bare Essentials"></A> +<HR SIZE="6"> +<A NAME="SEC98"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC97"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC99"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC103"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC97"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC103"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 8.2.1 Readline Bare Essentials </H3> +<!--docid::SEC98::--> +<P> + +In order to enter characters into the line, simply type them. The typed +character appears where the cursor was, and then the cursor moves one +space to the right. If you mistype a character, you can use your +erase character to back up and delete the mistyped character. +</P><P> + +Sometimes you may mistype a character, and +not notice the error until you have typed several other characters. In +that case, you can type <KBD>C-b</KBD> to move the cursor to the left, and then +correct your mistake. Afterwards, you can move the cursor to the right +with <KBD>C-f</KBD>. +</P><P> + +When you add text in the middle of a line, you will notice that characters +to the right of the cursor are `pushed over' to make room for the text +that you have inserted. Likewise, when you delete text behind the cursor, +characters to the right of the cursor are `pulled back' to fill in the +blank space created by the removal of the text. A list of the bare +essentials for editing the text of an input line follows. +</P><P> + +<DL COMPACT> +<DT><KBD>C-b</KBD> +<DD>Move back one character. +<DT><KBD>C-f</KBD> +<DD>Move forward one character. +<DT><KBD>DEL</KBD> or <KBD>Backspace</KBD> +<DD>Delete the character to the left of the cursor. +<DT><KBD>C-d</KBD> +<DD>Delete the character underneath the cursor. +<DT>Printing characters +<DD>Insert the character into the line at the cursor. +<DT><KBD>C-_</KBD> or <KBD>C-x C-u</KBD> +<DD>Undo the last editing command. You can undo all the way back to an +empty line. +</DL> +<P> + +(Depending on your configuration, the <KBD>Backspace</KBD> key be set to +delete the character to the left of the cursor and the <KBD>DEL</KBD> key set +to delete the character underneath the cursor, like <KBD>C-d</KBD>, rather +than the character to the left of the cursor.) +</P><P> + +<A NAME="Readline Movement Commands"></A> +<HR SIZE="6"> +<A NAME="SEC99"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC98"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC100"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC100"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC97"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC103"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 8.2.2 Readline Movement Commands </H3> +<!--docid::SEC99::--> +<P> + +The above table describes the most basic keystrokes that you need +in order to do editing of the input line. For your convenience, many +other commands have been added in addition to <KBD>C-b</KBD>, <KBD>C-f</KBD>, +<KBD>C-d</KBD>, and <KBD>DEL</KBD>. Here are some commands for moving more rapidly +about the line. +</P><P> + +<DL COMPACT> +<DT><KBD>C-a</KBD> +<DD>Move to the start of the line. +<DT><KBD>C-e</KBD> +<DD>Move to the end of the line. +<DT><KBD>M-f</KBD> +<DD>Move forward a word, where a word is composed of letters and digits. +<DT><KBD>M-b</KBD> +<DD>Move backward a word. +<DT><KBD>C-l</KBD> +<DD>Clear the screen, reprinting the current line at the top. +</DL> +<P> + +Notice how <KBD>C-f</KBD> moves forward a character, while <KBD>M-f</KBD> moves +forward a word. It is a loose convention that control keystrokes +operate on characters while meta keystrokes operate on words. +</P><P> + +<A NAME="Readline Killing Commands"></A> +<HR SIZE="6"> +<A NAME="SEC100"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC99"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC101"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC101"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC97"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC103"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 8.2.3 Readline Killing Commands </H3> +<!--docid::SEC100::--> +<P> + +<A NAME="IDX303"></A> +<A NAME="IDX304"></A> +</P><P> + +<EM>Killing</EM> text means to delete the text from the line, but to save +it away for later use, usually by <EM>yanking</EM> (re-inserting) +it back into the line. +(`Cut' and `paste' are more recent jargon for `kill' and `yank'.) +</P><P> + +If the description for a command says that it `kills' text, then you can +be sure that you can get the text back in a different (or the same) +place later. +</P><P> + +When you use a kill command, the text is saved in a <EM>kill-ring</EM>. +Any number of consecutive kills save all of the killed text together, so +that when you yank it back, you get it all. The kill +ring is not line specific; the text that you killed on a previously +typed line is available to be yanked back later, when you are typing +another line. +<A NAME="IDX305"></A> +</P><P> + +Here is the list of commands for killing text. +</P><P> + +<DL COMPACT> +<DT><KBD>C-k</KBD> +<DD>Kill the text from the current cursor position to the end of the line. +<P> + +<DT><KBD>M-d</KBD> +<DD>Kill from the cursor to the end of the current word, or, if between +words, to the end of the next word. +Word boundaries are the same as those used by <KBD>M-f</KBD>. +<P> + +<DT><KBD>M-<KBD>DEL</KBD></KBD> +<DD>Kill from the cursor the start of the current word, or, if between +words, to the start of the previous word. +Word boundaries are the same as those used by <KBD>M-b</KBD>. +<P> + +<DT><KBD>C-w</KBD> +<DD>Kill from the cursor to the previous whitespace. This is different than +<KBD>M-<KBD>DEL</KBD></KBD> because the word boundaries differ. +<P> + +</DL> +<P> + +Here is how to <EM>yank</EM> the text back into the line. Yanking +means to copy the most-recently-killed text from the kill buffer. +</P><P> + +<DL COMPACT> +<DT><KBD>C-y</KBD> +<DD>Yank the most recently killed text back into the buffer at the cursor. +<P> + +<DT><KBD>M-y</KBD> +<DD>Rotate the kill-ring, and yank the new top. You can only do this if +the prior command is <KBD>C-y</KBD> or <KBD>M-y</KBD>. +</DL> +<P> + +<A NAME="Readline Arguments"></A> +<HR SIZE="6"> +<A NAME="SEC101"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC100"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC102"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC102"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC97"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC103"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 8.2.4 Readline Arguments </H3> +<!--docid::SEC101::--> +<P> + +You can pass numeric arguments to Readline commands. Sometimes the +argument acts as a repeat count, other times it is the <I>sign</I> of the +argument that is significant. If you pass a negative argument to a +command which normally acts in a forward direction, that command will +act in a backward direction. For example, to kill text back to the +start of the line, you might type <SAMP>`M-- C-k'</SAMP>. +</P><P> + +The general way to pass numeric arguments to a command is to type meta +digits before the command. If the first `digit' typed is a minus +sign (<SAMP>`-'</SAMP>), then the sign of the argument will be negative. Once +you have typed one meta digit to get the argument started, you can type +the remainder of the digits, and then the command. For example, to give +the <KBD>C-d</KBD> command an argument of 10, you could type <SAMP>`M-1 0 C-d'</SAMP>, +which will delete the next ten characters on the input line. +</P><P> + +<A NAME="Searching"></A> +<HR SIZE="6"> +<A NAME="SEC102"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC101"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC103"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC103"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC97"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC103"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 8.2.5 Searching for Commands in the History </H3> +<!--docid::SEC102::--> +<P> + +Readline provides commands for searching through the command history +(see section <A HREF="bashref.html#SEC120">9.1 Bash History Facilities</A>) +for lines containing a specified string. +There are two search modes: <EM>incremental</EM> and <EM>non-incremental</EM>. +</P><P> + +Incremental searches begin before the user has finished typing the +search string. +As each character of the search string is typed, Readline displays +the next entry from the history matching the string typed so far. +An incremental search requires only as many characters as needed to +find the desired history entry. +To search backward in the history for a particular string, type +<KBD>C-r</KBD>. Typing <KBD>C-s</KBD> searches forward through the history. +The characters present in the value of the <CODE>isearch-terminators</CODE> variable +are used to terminate an incremental search. +If that variable has not been assigned a value, the <KBD>ESC</KBD> and +<KBD>C-J</KBD> characters will terminate an incremental search. +<KBD>C-g</KBD> will abort an incremental search and restore the original line. +When the search is terminated, the history entry containing the +search string becomes the current line. +</P><P> + +To find other matching entries in the history list, type <KBD>C-r</KBD> or +<KBD>C-s</KBD> as appropriate. +This will search backward or forward in the history for the next +entry matching the search string typed so far. +Any other key sequence bound to a Readline command will terminate +the search and execute that command. +For instance, a <KBD>RET</KBD> will terminate the search and accept +the line, thereby executing the command from the history list. +A movement command will terminate the search, make the last line found +the current line, and begin editing. +</P><P> + +Readline remembers the last incremental search string. If two +<KBD>C-r</KBD>s are typed without any intervening characters defining a new +search string, any remembered search string is used. +</P><P> + +Non-incremental searches read the entire search string before starting +to search for matching history lines. The search string may be +typed by the user or be part of the contents of the current line. +</P><P> + +<A NAME="Readline Init File"></A> +<HR SIZE="6"> +<A NAME="SEC103"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC102"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC104"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC107"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC95"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC107"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H2> 8.3 Readline Init File </H2> +<!--docid::SEC103::--> +<P> + +Although the Readline library comes with a set of Emacs-like +keybindings installed by default, it is possible to use a different set +of keybindings. +Any user can customize programs that use Readline by putting +commands in an <EM>inputrc</EM> file, conventionally in his home directory. +The name of this +file is taken from the value of the shell variable <CODE>INPUTRC</CODE>. If +that variable is unset, the default is <TT>`~/.inputrc'</TT>. If that +file does not exist or cannot be read, the ultimate default is +<TT>`/etc/inputrc'</TT>. +</P><P> + +When a program which uses the Readline library starts up, the +init file is read, and the key bindings are set. +</P><P> + +In addition, the <CODE>C-x C-r</CODE> command re-reads this init file, thus +incorporating any changes that you might have made to it. +</P><P> + +<BLOCKQUOTE><TABLE BORDER=0 CELLSPACING=0> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC104">8.3.1 Readline Init File Syntax</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Syntax for the commands in the inputrc file.</TD></TR> +</TABLE> + +<br> +<TABLE BORDER=0 CELLSPACING=0> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC105">8.3.2 Conditional Init Constructs</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Conditional key bindings in the inputrc file.</TD></TR> +</TABLE> + +<br> +<TABLE BORDER=0 CELLSPACING=0> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC106">8.3.3 Sample Init File</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">An example inputrc file.</TD></TR> +</TABLE></BLOCKQUOTE> +<P> + +<A NAME="Readline Init File Syntax"></A> +<HR SIZE="6"> +<A NAME="SEC104"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC103"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC105"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC107"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC103"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC107"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 8.3.1 Readline Init File Syntax </H3> +<!--docid::SEC104::--> +<P> + +There are only a few basic constructs allowed in the +Readline init file. Blank lines are ignored. +Lines beginning with a <SAMP>`#'</SAMP> are comments. +Lines beginning with a <SAMP>`$'</SAMP> indicate conditional +constructs (see section <A HREF="bashref.html#SEC105">8.3.2 Conditional Init Constructs</A>). Other lines +denote variable settings and key bindings. +</P><P> + +<DL COMPACT> +<DT>Variable Settings +<DD>You can modify the run-time behavior of Readline by +altering the values of variables in Readline +using the <CODE>set</CODE> command within the init file. +The syntax is simple: +<P> + +<TABLE><tr><td> </td><td class=example><pre>set <VAR>variable</VAR> <VAR>value</VAR> +</pre></td></tr></table></P><P> + +Here, for example, is how to +change from the default Emacs-like key binding to use +<CODE>vi</CODE> line editing commands: +</P><P> + +<TABLE><tr><td> </td><td class=example><pre>set editing-mode vi +</pre></td></tr></table></P><P> + +Variable names and values, where appropriate, are recognized without regard +to case. Unrecognized variable names are ignored. +</P><P> + +Boolean variables (those that can be set to on or off) are set to on if +the value is null or empty, <VAR>on</VAR> (case-insensitive), or 1. Any other +value results in the variable being set to off. +</P><P> + +The <CODE>bind -V</CODE> command lists the current Readline variable names +and values. See section <A HREF="bashref.html#SEC60">4.2 Bash Builtin Commands</A>. +</P><P> + +A great deal of run-time behavior is changeable with the following +variables. +</P><P> + +<A NAME="IDX306"></A> +<DL COMPACT> + +<DT><CODE>bell-style</CODE> +<DD><A NAME="IDX307"></A> +Controls what happens when Readline wants to ring the terminal bell. +If set to <SAMP>`none'</SAMP>, Readline never rings the bell. If set to +<SAMP>`visible'</SAMP>, Readline uses a visible bell if one is available. +If set to <SAMP>`audible'</SAMP> (the default), Readline attempts to ring +the terminal's bell. +<P> + +<DT><CODE>bind-tty-special-chars</CODE> +<DD><A NAME="IDX308"></A> +If set to <SAMP>`on'</SAMP>, Readline attempts to bind the control characters +treated specially by the kernel's terminal driver to their Readline +equivalents. +<P> + +<DT><CODE>comment-begin</CODE> +<DD><A NAME="IDX309"></A> +The string to insert at the beginning of the line when the +<CODE>insert-comment</CODE> command is executed. The default value +is <CODE>"#"</CODE>. +<P> + +<DT><CODE>completion-ignore-case</CODE> +<DD>If set to <SAMP>`on'</SAMP>, Readline performs filename matching and completion +in a case-insensitive fashion. +The default value is <SAMP>`off'</SAMP>. +<P> + +<DT><CODE>completion-prefix-display-length</CODE> +<DD><A NAME="IDX310"></A> +The length in characters of the common prefix of a list of possible +completions that is displayed without modification. When set to a +value greater than zero, common prefixes longer than this value are +replaced with an ellipsis when displaying possible completions. +<P> + +<DT><CODE>completion-query-items</CODE> +<DD><A NAME="IDX311"></A> +The number of possible completions that determines when the user is +asked whether the list of possibilities should be displayed. +If the number of possible completions is greater than this value, +Readline will ask the user whether or not he wishes to view +them; otherwise, they are simply listed. +This variable must be set to an integer value greater than or equal to 0. +A negative value means Readline should never ask. +The default limit is <CODE>100</CODE>. +<P> + +<DT><CODE>convert-meta</CODE> +<DD><A NAME="IDX312"></A> +If set to <SAMP>`on'</SAMP>, Readline will convert characters with the +eighth bit set to an ASCII key sequence by stripping the eighth +bit and prefixing an <KBD>ESC</KBD> character, converting them to a +meta-prefixed key sequence. The default value is <SAMP>`on'</SAMP>. +<P> + +<DT><CODE>disable-completion</CODE> +<DD><A NAME="IDX313"></A> +If set to <SAMP>`On'</SAMP>, Readline will inhibit word completion. +Completion characters will be inserted into the line as if they had +been mapped to <CODE>self-insert</CODE>. The default is <SAMP>`off'</SAMP>. +<P> + +<DT><CODE>editing-mode</CODE> +<DD><A NAME="IDX314"></A> +The <CODE>editing-mode</CODE> variable controls which default set of +key bindings is used. By default, Readline starts up in Emacs editing +mode, where the keystrokes are most similar to Emacs. This variable can be +set to either <SAMP>`emacs'</SAMP> or <SAMP>`vi'</SAMP>. +<P> + +<DT><CODE>echo-control-characters</CODE> +<DD>When set to <SAMP>`on'</SAMP>, on operating systems that indicate they support it, +readline echoes a character corresponding to a signal generated from the +keyboard. The default is <SAMP>`on'</SAMP>. +<P> + +<DT><CODE>enable-keypad</CODE> +<DD><A NAME="IDX315"></A> +When set to <SAMP>`on'</SAMP>, Readline will try to enable the application +keypad when it is called. Some systems need this to enable the +arrow keys. The default is <SAMP>`off'</SAMP>. +<P> + +<DT><CODE>enable-meta-key</CODE> +<DD>When set to <SAMP>`on'</SAMP>, Readline will try to enable any meta modifier +key the terminal claims to support when it is called. On many terminals, +the meta key is used to send eight-bit characters. +The default is <SAMP>`on'</SAMP>. +<P> + +<DT><CODE>expand-tilde</CODE> +<DD><A NAME="IDX316"></A> +If set to <SAMP>`on'</SAMP>, tilde expansion is performed when Readline +attempts word completion. The default is <SAMP>`off'</SAMP>. +<P> + +<DT><CODE>history-preserve-point</CODE> +<DD><A NAME="IDX317"></A> +If set to <SAMP>`on'</SAMP>, the history code attempts to place the point (the +current cursor position) at the +same location on each history line retrieved with <CODE>previous-history</CODE> +or <CODE>next-history</CODE>. The default is <SAMP>`off'</SAMP>. +<P> + +<DT><CODE>history-size</CODE> +<DD><A NAME="IDX318"></A> +Set the maximum number of history entries saved in the history list. If +set to zero, the number of entries in the history list is not limited. +<P> + +<DT><CODE>horizontal-scroll-mode</CODE> +<DD><A NAME="IDX319"></A> +This variable can be set to either <SAMP>`on'</SAMP> or <SAMP>`off'</SAMP>. Setting it +to <SAMP>`on'</SAMP> means that the text of the lines being edited will scroll +horizontally on a single screen line when they are longer than the width +of the screen, instead of wrapping onto a new screen line. By default, +this variable is set to <SAMP>`off'</SAMP>. +<P> + +<DT><CODE>input-meta</CODE> +<DD><A NAME="IDX320"></A> +<A NAME="IDX321"></A> +If set to <SAMP>`on'</SAMP>, Readline will enable eight-bit input (it +will not clear the eighth bit in the characters it reads), +regardless of what the terminal claims it can support. The +default value is <SAMP>`off'</SAMP>. The name <CODE>meta-flag</CODE> is a +synonym for this variable. +<P> + +<DT><CODE>isearch-terminators</CODE> +<DD><A NAME="IDX322"></A> +The string of characters that should terminate an incremental search without +subsequently executing the character as a command (see section <A HREF="bashref.html#SEC102">8.2.5 Searching for Commands in the History</A>). +If this variable has not been given a value, the characters <KBD>ESC</KBD> and +<KBD>C-J</KBD> will terminate an incremental search. +<P> + +<DT><CODE>keymap</CODE> +<DD><A NAME="IDX323"></A> +Sets Readline's idea of the current keymap for key binding commands. +Acceptable <CODE>keymap</CODE> names are +<CODE>emacs</CODE>, +<CODE>emacs-standard</CODE>, +<CODE>emacs-meta</CODE>, +<CODE>emacs-ctlx</CODE>, +<CODE>vi</CODE>, +<CODE>vi-move</CODE>, +<CODE>vi-command</CODE>, and +<CODE>vi-insert</CODE>. +<CODE>vi</CODE> is equivalent to <CODE>vi-command</CODE>; <CODE>emacs</CODE> is +equivalent to <CODE>emacs-standard</CODE>. The default value is <CODE>emacs</CODE>. +The value of the <CODE>editing-mode</CODE> variable also affects the +default keymap. +<P> + +<DT><CODE>mark-directories</CODE> +<DD>If set to <SAMP>`on'</SAMP>, completed directory names have a slash +appended. The default is <SAMP>`on'</SAMP>. +<P> + +<DT><CODE>mark-modified-lines</CODE> +<DD><A NAME="IDX324"></A> +This variable, when set to <SAMP>`on'</SAMP>, causes Readline to display an +asterisk (<SAMP>`*'</SAMP>) at the start of history lines which have been modified. +This variable is <SAMP>`off'</SAMP> by default. +<P> + +<DT><CODE>mark-symlinked-directories</CODE> +<DD><A NAME="IDX325"></A> +If set to <SAMP>`on'</SAMP>, completed names which are symbolic links +to directories have a slash appended (subject to the value of +<CODE>mark-directories</CODE>). +The default is <SAMP>`off'</SAMP>. +<P> + +<DT><CODE>match-hidden-files</CODE> +<DD><A NAME="IDX326"></A> +This variable, when set to <SAMP>`on'</SAMP>, causes Readline to match files whose +names begin with a <SAMP>`.'</SAMP> (hidden files) when performing filename +completion, unless the leading <SAMP>`.'</SAMP> is +supplied by the user in the filename to be completed. +This variable is <SAMP>`on'</SAMP> by default. +<P> + +<DT><CODE>output-meta</CODE> +<DD><A NAME="IDX327"></A> +If set to <SAMP>`on'</SAMP>, Readline will display characters with the +eighth bit set directly rather than as a meta-prefixed escape +sequence. The default is <SAMP>`off'</SAMP>. +<P> + +<DT><CODE>page-completions</CODE> +<DD><A NAME="IDX328"></A> +If set to <SAMP>`on'</SAMP>, Readline uses an internal <CODE>more</CODE>-like pager +to display a screenful of possible completions at a time. +This variable is <SAMP>`on'</SAMP> by default. +<P> + +<DT><CODE>print-completions-horizontally</CODE> +<DD>If set to <SAMP>`on'</SAMP>, Readline will display completions with matches +sorted horizontally in alphabetical order, rather than down the screen. +The default is <SAMP>`off'</SAMP>. +<P> + +<DT><CODE>revert-all-at-newline</CODE> +<DD><A NAME="IDX329"></A> +If set to <SAMP>`on'</SAMP>, Readline will undo all changes to history lines +before returning when <CODE>accept-line</CODE> is executed. By default, +history lines may be modified and retain individual undo lists across +calls to <CODE>readline</CODE>. The default is <SAMP>`off'</SAMP>. +<P> + +<DT><CODE>show-all-if-ambiguous</CODE> +<DD><A NAME="IDX330"></A> +This alters the default behavior of the completion functions. If +set to <SAMP>`on'</SAMP>, +words which have more than one possible completion cause the +matches to be listed immediately instead of ringing the bell. +The default value is <SAMP>`off'</SAMP>. +<P> + +<DT><CODE>show-all-if-unmodified</CODE> +<DD><A NAME="IDX331"></A> +This alters the default behavior of the completion functions in +a fashion similar to <VAR>show-all-if-ambiguous</VAR>. +If set to <SAMP>`on'</SAMP>, +words which have more than one possible completion without any +possible partial completion (the possible completions don't share +a common prefix) cause the matches to be listed immediately instead +of ringing the bell. +The default value is <SAMP>`off'</SAMP>. +<P> + +<DT><CODE>skip-completed-text</CODE> +<DD><A NAME="IDX332"></A> +If set to <SAMP>`on'</SAMP>, this alters the default completion behavior when +inserting a single match into the line. It's only active when +performing completion in the middle of a word. If enabled, readline +does not insert characters from the completion that match characters +after point in the word being completed, so portions of the word +following the cursor are not duplicated. +For instance, if this is enabled, attempting completion when the cursor +is after the <SAMP>`e'</SAMP> in <SAMP>`Makefile'</SAMP> will result in <SAMP>`Makefile'</SAMP> +rather than <SAMP>`Makefilefile'</SAMP>, assuming there is a single possible +completion. +The default value is <SAMP>`off'</SAMP>. +<P> + +<DT><CODE>visible-stats</CODE> +<DD><A NAME="IDX333"></A> +If set to <SAMP>`on'</SAMP>, a character denoting a file's type +is appended to the filename when listing possible +completions. The default is <SAMP>`off'</SAMP>. +<P> + +</DL> +<P> + +<DT>Key Bindings +<DD>The syntax for controlling key bindings in the init file is +simple. First you need to find the name of the command that you +want to change. The following sections contain tables of the command +name, the default keybinding, if any, and a short description of what +the command does. +<P> + +Once you know the name of the command, simply place on a line +in the init file the name of the key +you wish to bind the command to, a colon, and then the name of the +command. +There can be no space between the key name and the colon -- that will be +interpreted as part of the key name. +The name of the key can be expressed in different ways, depending on +what you find most comfortable. +</P><P> + +In addition to command names, readline allows keys to be bound +to a string that is inserted when the key is pressed (a <VAR>macro</VAR>). +</P><P> + +The <CODE>bind -p</CODE> command displays Readline function names and +bindings in a format that can put directly into an initialization file. +See section <A HREF="bashref.html#SEC60">4.2 Bash Builtin Commands</A>. +</P><P> + +<DL COMPACT> +<DT><VAR>keyname</VAR>: <VAR>function-name</VAR> or <VAR>macro</VAR> +<DD><VAR>keyname</VAR> is the name of a key spelled out in English. For example: +<TABLE><tr><td> </td><td class=example><pre>Control-u: universal-argument +Meta-Rubout: backward-kill-word +Control-o: "> output" +</pre></td></tr></table><P> + +In the above example, <KBD>C-u</KBD> is bound to the function +<CODE>universal-argument</CODE>, +<KBD>M-DEL</KBD> is bound to the function <CODE>backward-kill-word</CODE>, and +<KBD>C-o</KBD> is bound to run the macro +expressed on the right hand side (that is, to insert the text +<SAMP>`> output'</SAMP> into the line). +</P><P> + +A number of symbolic character names are recognized while +processing this key binding syntax: +<VAR>DEL</VAR>, +<VAR>ESC</VAR>, +<VAR>ESCAPE</VAR>, +<VAR>LFD</VAR>, +<VAR>NEWLINE</VAR>, +<VAR>RET</VAR>, +<VAR>RETURN</VAR>, +<VAR>RUBOUT</VAR>, +<VAR>SPACE</VAR>, +<VAR>SPC</VAR>, +and +<VAR>TAB</VAR>. +</P><P> + +<DT>"<VAR>keyseq</VAR>": <VAR>function-name</VAR> or <VAR>macro</VAR> +<DD><VAR>keyseq</VAR> differs from <VAR>keyname</VAR> above in that strings +denoting an entire key sequence can be specified, by placing +the key sequence in double quotes. Some GNU Emacs style key +escapes can be used, as in the following example, but the +special character names are not recognized. +<P> + +<TABLE><tr><td> </td><td class=example><pre>"\C-u": universal-argument +"\C-x\C-r": re-read-init-file +"\e[11~": "Function Key 1" +</pre></td></tr></table></P><P> + +In the above example, <KBD>C-u</KBD> is again bound to the function +<CODE>universal-argument</CODE> (just as it was in the first example), +<SAMP>`<KBD>C-x</KBD> <KBD>C-r</KBD>'</SAMP> is bound to the function <CODE>re-read-init-file</CODE>, +and <SAMP>`<KBD>ESC</KBD> <KBD>[</KBD> <KBD>1</KBD> <KBD>1</KBD> <KBD>~</KBD>'</SAMP> is bound to insert +the text <SAMP>`Function Key 1'</SAMP>. +</P><P> + +</DL> +<P> + +The following GNU Emacs style escape sequences are available when +specifying key sequences: +</P><P> + +<DL COMPACT> +<DT><CODE><KBD>\C-</KBD></CODE> +<DD>control prefix +<DT><CODE><KBD>\M-</KBD></CODE> +<DD>meta prefix +<DT><CODE><KBD>\e</KBD></CODE> +<DD>an escape character +<DT><CODE><KBD>\\</KBD></CODE> +<DD>backslash +<DT><CODE><KBD>\"</KBD></CODE> +<DD><KBD>"</KBD>, a double quotation mark +<DT><CODE><KBD>\'</KBD></CODE> +<DD><KBD>'</KBD>, a single quote or apostrophe +</DL> +<P> + +In addition to the GNU Emacs style escape sequences, a second +set of backslash escapes is available: +</P><P> + +<DL COMPACT> +<DT><CODE>\a</CODE> +<DD>alert (bell) +<DT><CODE>\b</CODE> +<DD>backspace +<DT><CODE>\d</CODE> +<DD>delete +<DT><CODE>\f</CODE> +<DD>form feed +<DT><CODE>\n</CODE> +<DD>newline +<DT><CODE>\r</CODE> +<DD>carriage return +<DT><CODE>\t</CODE> +<DD>horizontal tab +<DT><CODE>\v</CODE> +<DD>vertical tab +<DT><CODE>\<VAR>nnn</VAR></CODE> +<DD>the eight-bit character whose value is the octal value <VAR>nnn</VAR> +(one to three digits) +<DT><CODE>\x<VAR>HH</VAR></CODE> +<DD>the eight-bit character whose value is the hexadecimal value <VAR>HH</VAR> +(one or two hex digits) +</DL> +<P> + +When entering the text of a macro, single or double quotes must +be used to indicate a macro definition. +Unquoted text is assumed to be a function name. +In the macro body, the backslash escapes described above are expanded. +Backslash will quote any other character in the macro text, +including <SAMP>`"'</SAMP> and <SAMP>`''</SAMP>. +For example, the following binding will make <SAMP>`<KBD>C-x</KBD> \'</SAMP> +insert a single <SAMP>`\'</SAMP> into the line: +<TABLE><tr><td> </td><td class=example><pre>"\C-x\\": "\\" +</pre></td></tr></table></P><P> + +</DL> +<P> + +<A NAME="Conditional Init Constructs"></A> +<HR SIZE="6"> +<A NAME="SEC105"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC104"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC106"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC106"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC103"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC107"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 8.3.2 Conditional Init Constructs </H3> +<!--docid::SEC105::--> +<P> + +Readline implements a facility similar in spirit to the conditional +compilation features of the C preprocessor which allows key +bindings and variable settings to be performed as the result +of tests. There are four parser directives used. +</P><P> + +<DL COMPACT> +<DT><CODE>$if</CODE> +<DD>The <CODE>$if</CODE> construct allows bindings to be made based on the +editing mode, the terminal being used, or the application using +Readline. The text of the test extends to the end of the line; +no characters are required to isolate it. +<P> + +<DL COMPACT> +<DT><CODE>mode</CODE> +<DD>The <CODE>mode=</CODE> form of the <CODE>$if</CODE> directive is used to test +whether Readline is in <CODE>emacs</CODE> or <CODE>vi</CODE> mode. +This may be used in conjunction +with the <SAMP>`set keymap'</SAMP> command, for instance, to set bindings in +the <CODE>emacs-standard</CODE> and <CODE>emacs-ctlx</CODE> keymaps only if +Readline is starting out in <CODE>emacs</CODE> mode. +<P> + +<DT><CODE>term</CODE> +<DD>The <CODE>term=</CODE> form may be used to include terminal-specific +key bindings, perhaps to bind the key sequences output by the +terminal's function keys. The word on the right side of the +<SAMP>`='</SAMP> is tested against both the full name of the terminal and +the portion of the terminal name before the first <SAMP>`-'</SAMP>. This +allows <CODE>sun</CODE> to match both <CODE>sun</CODE> and <CODE>sun-cmd</CODE>, +for instance. +<P> + +<DT><CODE>application</CODE> +<DD>The <VAR>application</VAR> construct is used to include +application-specific settings. Each program using the Readline +library sets the <VAR>application name</VAR>, and you can test for +a particular value. +This could be used to bind key sequences to functions useful for +a specific program. For instance, the following command adds a +key sequence that quotes the current or previous word in Bash: +<TABLE><tr><td> </td><td class=example><pre>$if Bash +# Quote the current or previous word +"\C-xq": "\eb\"\ef\"" +$endif +</pre></td></tr></table></DL> +<P> + +<DT><CODE>$endif</CODE> +<DD>This command, as seen in the previous example, terminates an +<CODE>$if</CODE> command. +<P> + +<DT><CODE>$else</CODE> +<DD>Commands in this branch of the <CODE>$if</CODE> directive are executed if +the test fails. +<P> + +<DT><CODE>$include</CODE> +<DD>This directive takes a single filename as an argument and reads commands +and bindings from that file. +For example, the following directive reads from <TT>`/etc/inputrc'</TT>: +<TABLE><tr><td> </td><td class=example><pre>$include /etc/inputrc +</pre></td></tr></table></DL> +<P> + +<A NAME="Sample Init File"></A> +<HR SIZE="6"> +<A NAME="SEC106"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC105"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC107"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC107"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC103"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC107"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 8.3.3 Sample Init File </H3> +<!--docid::SEC106::--> +<P> + +Here is an example of an <VAR>inputrc</VAR> file. This illustrates key +binding, variable assignment, and conditional syntax. +</P><P> + +<TABLE><tr><td> </td><td class=example><pre># This file controls the behaviour of line input editing for +# programs that use the GNU Readline library. Existing +# programs include FTP, Bash, and GDB. +# +# You can re-read the inputrc file with C-x C-r. +# Lines beginning with '#' are comments. +# +# First, include any systemwide bindings and variable +# assignments from /etc/Inputrc +$include /etc/Inputrc + +# +# Set various bindings for emacs mode. + +set editing-mode emacs + +$if mode=emacs + +Meta-Control-h: backward-kill-word Text after the function name is ignored + +# +# Arrow keys in keypad mode +# +#"\M-OD": backward-char +#"\M-OC": forward-char +#"\M-OA": previous-history +#"\M-OB": next-history +# +# Arrow keys in ANSI mode +# +"\M-[D": backward-char +"\M-[C": forward-char +"\M-[A": previous-history +"\M-[B": next-history +# +# Arrow keys in 8 bit keypad mode +# +#"\M-\C-OD": backward-char +#"\M-\C-OC": forward-char +#"\M-\C-OA": previous-history +#"\M-\C-OB": next-history +# +# Arrow keys in 8 bit ANSI mode +# +#"\M-\C-[D": backward-char +#"\M-\C-[C": forward-char +#"\M-\C-[A": previous-history +#"\M-\C-[B": next-history + +C-q: quoted-insert + +$endif + +# An old-style binding. This happens to be the default. +TAB: complete + +# Macros that are convenient for shell interaction +$if Bash +# edit the path +"\C-xp": "PATH=${PATH}\e\C-e\C-a\ef\C-f" +# prepare to type a quoted word -- +# insert open and close double quotes +# and move to just after the open quote +"\C-x\"": "\"\"\C-b" +# insert a backslash (testing backslash escapes +# in sequences and macros) +"\C-x\\": "\\" +# Quote the current or previous word +"\C-xq": "\eb\"\ef\"" +# Add a binding to refresh the line, which is unbound +"\C-xr": redraw-current-line +# Edit variable on current line. +"\M-\C-v": "\C-a\C-k$\C-y\M-\C-e\C-a\C-y=" +$endif + +# use a visible bell if one is available +set bell-style visible + +# don't strip characters to 7 bits when reading +set input-meta on + +# allow iso-latin1 characters to be inserted rather +# than converted to prefix-meta sequences +set convert-meta off + +# display characters with the eighth bit set directly +# rather than as meta-prefixed characters +set output-meta on + +# if there are more than 150 possible completions for +# a word, ask the user if he wants to see all of them +set completion-query-items 150 + +# For FTP +$if Ftp +"\C-xg": "get \M-?" +"\C-xt": "put \M-?" +"\M-.": yank-last-arg +$endif +</pre></td></tr></table></P><P> + +<A NAME="Bindable Readline Commands"></A> +<HR SIZE="6"> +<A NAME="SEC107"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC106"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC108"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC116"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC95"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC116"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H2> 8.4 Bindable Readline Commands </H2> +<!--docid::SEC107::--> +<P> + +<BLOCKQUOTE><TABLE BORDER=0 CELLSPACING=0> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC108">8.4.1 Commands For Moving</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Moving about the line.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC109">8.4.2 Commands For Manipulating The History</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Getting at previous lines.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC110">8.4.3 Commands For Changing Text</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Commands for changing text.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC111">8.4.4 Killing And Yanking</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Commands for killing and yanking.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC112">8.4.5 Specifying Numeric Arguments</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Specifying numeric arguments, repeat counts.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC113">8.4.6 Letting Readline Type For You</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Getting Readline to do the typing for you.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC114">8.4.7 Keyboard Macros</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Saving and re-executing typed characters</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC115">8.4.8 Some Miscellaneous Commands</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Other miscellaneous commands.</TD></TR> +</TABLE></BLOCKQUOTE> +<P> + +This section describes Readline commands that may be bound to key +sequences. +You can list your key bindings by executing +<CODE>bind -P</CODE> or, for a more terse format, suitable for an +<VAR>inputrc</VAR> file, <CODE>bind -p</CODE>. (See section <A HREF="bashref.html#SEC60">4.2 Bash Builtin Commands</A>.) +Command names without an accompanying key sequence are unbound by default. +</P><P> + +In the following descriptions, <EM>point</EM> refers to the current cursor +position, and <EM>mark</EM> refers to a cursor position saved by the +<CODE>set-mark</CODE> command. +The text between the point and mark is referred to as the <EM>region</EM>. +</P><P> + +<A NAME="Commands For Moving"></A> +<HR SIZE="6"> +<A NAME="SEC108"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC107"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC109"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC116"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC107"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC116"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 8.4.1 Commands For Moving </H3> +<!--docid::SEC108::--> +<DL COMPACT> +<A NAME="IDX334"></A> +<DT><CODE>beginning-of-line (C-a)</CODE> +<DD><A NAME="IDX335"></A> +Move to the start of the current line. +<P> + +<A NAME="IDX336"></A> +<DT><CODE>end-of-line (C-e)</CODE> +<DD><A NAME="IDX337"></A> +Move to the end of the line. +<P> + +<A NAME="IDX338"></A> +<DT><CODE>forward-char (C-f)</CODE> +<DD><A NAME="IDX339"></A> +Move forward a character. +<P> + +<A NAME="IDX340"></A> +<DT><CODE>backward-char (C-b)</CODE> +<DD><A NAME="IDX341"></A> +Move back a character. +<P> + +<A NAME="IDX342"></A> +<DT><CODE>forward-word (M-f)</CODE> +<DD><A NAME="IDX343"></A> +Move forward to the end of the next word. +Words are composed of letters and digits. +<P> + +<A NAME="IDX344"></A> +<DT><CODE>backward-word (M-b)</CODE> +<DD><A NAME="IDX345"></A> +Move back to the start of the current or previous word. +Words are composed of letters and digits. +<P> + +<A NAME="IDX346"></A> +<DT><CODE>shell-forward-word ()</CODE> +<DD><A NAME="IDX347"></A> +Move forward to the end of the next word. +Words are delimited by non-quoted shell metacharacters. +<P> + +<A NAME="IDX348"></A> +<DT><CODE>shell-backward-word ()</CODE> +<DD><A NAME="IDX349"></A> +Move back to the start of the current or previous word. +Words are delimited by non-quoted shell metacharacters. +<P> + +<A NAME="IDX350"></A> +<DT><CODE>clear-screen (C-l)</CODE> +<DD><A NAME="IDX351"></A> +Clear the screen and redraw the current line, +leaving the current line at the top of the screen. +<P> + +<A NAME="IDX352"></A> +<DT><CODE>redraw-current-line ()</CODE> +<DD><A NAME="IDX353"></A> +Refresh the current line. By default, this is unbound. +<P> + +</DL> +<P> + +<A NAME="Commands For History"></A> +<HR SIZE="6"> +<A NAME="SEC109"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC108"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC110"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC110"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC107"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC116"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 8.4.2 Commands For Manipulating The History </H3> +<!--docid::SEC109::--> +<P> + +<DL COMPACT> +<A NAME="IDX354"></A> +<DT><CODE>accept-line (Newline or Return)</CODE> +<DD><A NAME="IDX355"></A> +Accept the line regardless of where the cursor is. +If this line is +non-empty, add it to the history list according to the setting of +the <CODE>HISTCONTROL</CODE> and <CODE>HISTIGNORE</CODE> variables. +If this line is a modified history line, then restore the history line +to its original state. +<P> + +<A NAME="IDX356"></A> +<DT><CODE>previous-history (C-p)</CODE> +<DD><A NAME="IDX357"></A> +Move `back' through the history list, fetching the previous command. +<P> + +<A NAME="IDX358"></A> +<DT><CODE>next-history (C-n)</CODE> +<DD><A NAME="IDX359"></A> +Move `forward' through the history list, fetching the next command. +<P> + +<A NAME="IDX360"></A> +<DT><CODE>beginning-of-history (M-<)</CODE> +<DD><A NAME="IDX361"></A> +Move to the first line in the history. +<P> + +<A NAME="IDX362"></A> +<DT><CODE>end-of-history (M->)</CODE> +<DD><A NAME="IDX363"></A> +Move to the end of the input history, i.e., the line currently +being entered. +<P> + +<A NAME="IDX364"></A> +<DT><CODE>reverse-search-history (C-r)</CODE> +<DD><A NAME="IDX365"></A> +Search backward starting at the current line and moving `up' through +the history as necessary. This is an incremental search. +<P> + +<A NAME="IDX366"></A> +<DT><CODE>forward-search-history (C-s)</CODE> +<DD><A NAME="IDX367"></A> +Search forward starting at the current line and moving `down' through +the the history as necessary. This is an incremental search. +<P> + +<A NAME="IDX368"></A> +<DT><CODE>non-incremental-reverse-search-history (M-p)</CODE> +<DD><A NAME="IDX369"></A> +Search backward starting at the current line and moving `up' +through the history as necessary using a non-incremental search +for a string supplied by the user. +<P> + +<A NAME="IDX370"></A> +<DT><CODE>non-incremental-forward-search-history (M-n)</CODE> +<DD><A NAME="IDX371"></A> +Search forward starting at the current line and moving `down' +through the the history as necessary using a non-incremental search +for a string supplied by the user. +<P> + +<A NAME="IDX372"></A> +<DT><CODE>history-search-forward ()</CODE> +<DD><A NAME="IDX373"></A> +Search forward through the history for the string of characters +between the start of the current line and the point. +This is a non-incremental search. +By default, this command is unbound. +<P> + +<A NAME="IDX374"></A> +<DT><CODE>history-search-backward ()</CODE> +<DD><A NAME="IDX375"></A> +Search backward through the history for the string of characters +between the start of the current line and the point. This +is a non-incremental search. By default, this command is unbound. +<P> + +<A NAME="IDX376"></A> +<DT><CODE>yank-nth-arg (M-C-y)</CODE> +<DD><A NAME="IDX377"></A> +Insert the first argument to the previous command (usually +the second word on the previous line) at point. +With an argument <VAR>n</VAR>, +insert the <VAR>n</VAR>th word from the previous command (the words +in the previous command begin with word 0). A negative argument +inserts the <VAR>n</VAR>th word from the end of the previous command. +Once the argument <VAR>n</VAR> is computed, the argument is extracted +as if the <SAMP>`!<VAR>n</VAR>'</SAMP> history expansion had been specified. +<P> + +<A NAME="IDX378"></A> +<DT><CODE>yank-last-arg (M-. or M-_)</CODE> +<DD><A NAME="IDX379"></A> +Insert last argument to the previous command (the last word of the +previous history entry). With an +argument, behave exactly like <CODE>yank-nth-arg</CODE>. +Successive calls to <CODE>yank-last-arg</CODE> move back through the history +list, inserting the last argument of each line in turn. +The history expansion facilities are used to extract the last argument, +as if the <SAMP>`!$'</SAMP> history expansion had been specified. +<P> + +</DL> +<P> + +<A NAME="Commands For Text"></A> +<HR SIZE="6"> +<A NAME="SEC110"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC109"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC111"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC111"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC107"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC116"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 8.4.3 Commands For Changing Text </H3> +<!--docid::SEC110::--> +<P> + +<DL COMPACT> +<A NAME="IDX380"></A> +<DT><CODE>delete-char (C-d)</CODE> +<DD><A NAME="IDX381"></A> +Delete the character at point. If point is at the +beginning of the line, there are no characters in the line, and +the last character typed was not bound to <CODE>delete-char</CODE>, then +return EOF. +<P> + +<A NAME="IDX382"></A> +<DT><CODE>backward-delete-char (Rubout)</CODE> +<DD><A NAME="IDX383"></A> +Delete the character behind the cursor. A numeric argument means +to kill the characters instead of deleting them. +<P> + +<A NAME="IDX384"></A> +<DT><CODE>forward-backward-delete-char ()</CODE> +<DD><A NAME="IDX385"></A> +Delete the character under the cursor, unless the cursor is at the +end of the line, in which case the character behind the cursor is +deleted. By default, this is not bound to a key. +<P> + +<A NAME="IDX386"></A> +<DT><CODE>quoted-insert (C-q or C-v)</CODE> +<DD><A NAME="IDX387"></A> +Add the next character typed to the line verbatim. This is +how to insert key sequences like <KBD>C-q</KBD>, for example. +<P> + +<A NAME="IDX388"></A> +<DT><CODE>self-insert (a, b, A, 1, !, <small>...</small>)</CODE> +<DD><A NAME="IDX389"></A> +Insert yourself. +<P> + +<A NAME="IDX390"></A> +<DT><CODE>transpose-chars (C-t)</CODE> +<DD><A NAME="IDX391"></A> +Drag the character before the cursor forward over +the character at the cursor, moving the +cursor forward as well. If the insertion point +is at the end of the line, then this +transposes the last two characters of the line. +Negative arguments have no effect. +<P> + +<A NAME="IDX392"></A> +<DT><CODE>transpose-words (M-t)</CODE> +<DD><A NAME="IDX393"></A> +Drag the word before point past the word after point, +moving point past that word as well. +If the insertion point is at the end of the line, this transposes +the last two words on the line. +<P> + +<A NAME="IDX394"></A> +<DT><CODE>upcase-word (M-u)</CODE> +<DD><A NAME="IDX395"></A> +Uppercase the current (or following) word. With a negative argument, +uppercase the previous word, but do not move the cursor. +<P> + +<A NAME="IDX396"></A> +<DT><CODE>downcase-word (M-l)</CODE> +<DD><A NAME="IDX397"></A> +Lowercase the current (or following) word. With a negative argument, +lowercase the previous word, but do not move the cursor. +<P> + +<A NAME="IDX398"></A> +<DT><CODE>capitalize-word (M-c)</CODE> +<DD><A NAME="IDX399"></A> +Capitalize the current (or following) word. With a negative argument, +capitalize the previous word, but do not move the cursor. +<P> + +<A NAME="IDX400"></A> +<DT><CODE>overwrite-mode ()</CODE> +<DD><A NAME="IDX401"></A> +Toggle overwrite mode. With an explicit positive numeric argument, +switches to overwrite mode. With an explicit non-positive numeric +argument, switches to insert mode. This command affects only +<CODE>emacs</CODE> mode; <CODE>vi</CODE> mode does overwrite differently. +Each call to <CODE>readline()</CODE> starts in insert mode. +<P> + +In overwrite mode, characters bound to <CODE>self-insert</CODE> replace +the text at point rather than pushing the text to the right. +Characters bound to <CODE>backward-delete-char</CODE> replace the character +before point with a space. +</P><P> + +By default, this command is unbound. +</P><P> + +</DL> +<P> + +<A NAME="Commands For Killing"></A> +<HR SIZE="6"> +<A NAME="SEC111"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC110"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC112"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC112"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC107"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC116"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 8.4.4 Killing And Yanking </H3> +<!--docid::SEC111::--> +<P> + +<DL COMPACT> + +<A NAME="IDX402"></A> +<DT><CODE>kill-line (C-k)</CODE> +<DD><A NAME="IDX403"></A> +Kill the text from point to the end of the line. +<P> + +<A NAME="IDX404"></A> +<DT><CODE>backward-kill-line (C-x Rubout)</CODE> +<DD><A NAME="IDX405"></A> +Kill backward to the beginning of the line. +<P> + +<A NAME="IDX406"></A> +<DT><CODE>unix-line-discard (C-u)</CODE> +<DD><A NAME="IDX407"></A> +Kill backward from the cursor to the beginning of the current line. +<P> + +<A NAME="IDX408"></A> +<DT><CODE>kill-whole-line ()</CODE> +<DD><A NAME="IDX409"></A> +Kill all characters on the current line, no matter where point is. +By default, this is unbound. +<P> + +<A NAME="IDX410"></A> +<DT><CODE>kill-word (M-d)</CODE> +<DD><A NAME="IDX411"></A> +Kill from point to the end of the current word, or if between +words, to the end of the next word. +Word boundaries are the same as <CODE>forward-word</CODE>. +<P> + +<A NAME="IDX412"></A> +<DT><CODE>backward-kill-word (M-<KBD>DEL</KBD>)</CODE> +<DD><A NAME="IDX413"></A> +Kill the word behind point. +Word boundaries are the same as <CODE>backward-word</CODE>. +<P> + +<A NAME="IDX414"></A> +<DT><CODE>shell-kill-word ()</CODE> +<DD><A NAME="IDX415"></A> +Kill from point to the end of the current word, or if between +words, to the end of the next word. +Word boundaries are the same as <CODE>shell-forward-word</CODE>. +<P> + +<A NAME="IDX416"></A> +<DT><CODE>backward-kill-word ()</CODE> +<DD><A NAME="IDX417"></A> +Kill the word behind point. +Word boundaries are the same as <CODE>shell-backward-word</CODE>. +<P> + +<A NAME="IDX418"></A> +<DT><CODE>unix-word-rubout (C-w)</CODE> +<DD><A NAME="IDX419"></A> +Kill the word behind point, using white space as a word boundary. +The killed text is saved on the kill-ring. +<P> + +<A NAME="IDX420"></A> +<DT><CODE>unix-filename-rubout ()</CODE> +<DD><A NAME="IDX421"></A> +Kill the word behind point, using white space and the slash character +as the word boundaries. +The killed text is saved on the kill-ring. +<P> + +<A NAME="IDX422"></A> +<DT><CODE>delete-horizontal-space ()</CODE> +<DD><A NAME="IDX423"></A> +Delete all spaces and tabs around point. By default, this is unbound. +<P> + +<A NAME="IDX424"></A> +<DT><CODE>kill-region ()</CODE> +<DD><A NAME="IDX425"></A> +Kill the text in the current region. +By default, this command is unbound. +<P> + +<A NAME="IDX426"></A> +<DT><CODE>copy-region-as-kill ()</CODE> +<DD><A NAME="IDX427"></A> +Copy the text in the region to the kill buffer, so it can be yanked +right away. By default, this command is unbound. +<P> + +<A NAME="IDX428"></A> +<DT><CODE>copy-backward-word ()</CODE> +<DD><A NAME="IDX429"></A> +Copy the word before point to the kill buffer. +The word boundaries are the same as <CODE>backward-word</CODE>. +By default, this command is unbound. +<P> + +<A NAME="IDX430"></A> +<DT><CODE>copy-forward-word ()</CODE> +<DD><A NAME="IDX431"></A> +Copy the word following point to the kill buffer. +The word boundaries are the same as <CODE>forward-word</CODE>. +By default, this command is unbound. +<P> + +<A NAME="IDX432"></A> +<DT><CODE>yank (C-y)</CODE> +<DD><A NAME="IDX433"></A> +Yank the top of the kill ring into the buffer at point. +<P> + +<A NAME="IDX434"></A> +<DT><CODE>yank-pop (M-y)</CODE> +<DD><A NAME="IDX435"></A> +Rotate the kill-ring, and yank the new top. You can only do this if +the prior command is <CODE>yank</CODE> or <CODE>yank-pop</CODE>. +</DL> +<P> + +<A NAME="Numeric Arguments"></A> +<HR SIZE="6"> +<A NAME="SEC112"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC111"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC113"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC113"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC107"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC116"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 8.4.5 Specifying Numeric Arguments </H3> +<!--docid::SEC112::--> +<DL COMPACT> + +<A NAME="IDX436"></A> +<DT><CODE>digit-argument (<KBD>M-0</KBD>, <KBD>M-1</KBD>, <small>...</small> <KBD>M--</KBD>)</CODE> +<DD><A NAME="IDX437"></A> +Add this digit to the argument already accumulating, or start a new +argument. <KBD>M--</KBD> starts a negative argument. +<P> + +<A NAME="IDX438"></A> +<DT><CODE>universal-argument ()</CODE> +<DD><A NAME="IDX439"></A> +This is another way to specify an argument. +If this command is followed by one or more digits, optionally with a +leading minus sign, those digits define the argument. +If the command is followed by digits, executing <CODE>universal-argument</CODE> +again ends the numeric argument, but is otherwise ignored. +As a special case, if this command is immediately followed by a +character that is neither a digit or minus sign, the argument count +for the next command is multiplied by four. +The argument count is initially one, so executing this function the +first time makes the argument count four, a second time makes the +argument count sixteen, and so on. +By default, this is not bound to a key. +</DL> +<P> + +<A NAME="Commands For Completion"></A> +<HR SIZE="6"> +<A NAME="SEC113"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC112"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC114"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC114"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC107"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC116"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 8.4.6 Letting Readline Type For You </H3> +<!--docid::SEC113::--> +<P> + +<DL COMPACT> +<A NAME="IDX440"></A> +<DT><CODE>complete (<KBD>TAB</KBD>)</CODE> +<DD><A NAME="IDX441"></A> +Attempt to perform completion on the text before point. +The actual completion performed is application-specific. +Bash attempts completion treating the text as a variable (if the +text begins with <SAMP>`$'</SAMP>), username (if the text begins with +<SAMP>`~'</SAMP>), hostname (if the text begins with <SAMP>`@'</SAMP>), or +command (including aliases and functions) in turn. If none +of these produces a match, filename completion is attempted. +<P> + +<A NAME="IDX442"></A> +<DT><CODE>possible-completions (M-?)</CODE> +<DD><A NAME="IDX443"></A> +List the possible completions of the text before point. +<P> + +<A NAME="IDX444"></A> +<DT><CODE>insert-completions (M-*)</CODE> +<DD><A NAME="IDX445"></A> +Insert all completions of the text before point that would have +been generated by <CODE>possible-completions</CODE>. +<P> + +<A NAME="IDX446"></A> +<DT><CODE>menu-complete ()</CODE> +<DD><A NAME="IDX447"></A> +Similar to <CODE>complete</CODE>, but replaces the word to be completed +with a single match from the list of possible completions. +Repeated execution of <CODE>menu-complete</CODE> steps through the list +of possible completions, inserting each match in turn. +At the end of the list of completions, the bell is rung +(subject to the setting of <CODE>bell-style</CODE>) +and the original text is restored. +An argument of <VAR>n</VAR> moves <VAR>n</VAR> positions forward in the list +of matches; a negative argument may be used to move backward +through the list. +This command is intended to be bound to <KBD>TAB</KBD>, but is unbound +by default. +<P> + +<A NAME="IDX448"></A> +<DT><CODE>menu-complete-backward ()</CODE> +<DD><A NAME="IDX449"></A> +Identical to <CODE>menu-complete</CODE>, but moves backward through the list +of possible completions, as if <CODE>menu-complete</CODE> had been given a +negative argument. +<P> + +<A NAME="IDX450"></A> +<DT><CODE>delete-char-or-list ()</CODE> +<DD><A NAME="IDX451"></A> +Deletes the character under the cursor if not at the beginning or +end of the line (like <CODE>delete-char</CODE>). +If at the end of the line, behaves identically to +<CODE>possible-completions</CODE>. +This command is unbound by default. +<P> + +<A NAME="IDX452"></A> +<DT><CODE>complete-filename (M-/)</CODE> +<DD><A NAME="IDX453"></A> +Attempt filename completion on the text before point. +<P> + +<A NAME="IDX454"></A> +<DT><CODE>possible-filename-completions (C-x /)</CODE> +<DD><A NAME="IDX455"></A> +List the possible completions of the text before point, +treating it as a filename. +<P> + +<A NAME="IDX456"></A> +<DT><CODE>complete-username (M-~)</CODE> +<DD><A NAME="IDX457"></A> +Attempt completion on the text before point, treating +it as a username. +<P> + +<A NAME="IDX458"></A> +<DT><CODE>possible-username-completions (C-x ~)</CODE> +<DD><A NAME="IDX459"></A> +List the possible completions of the text before point, +treating it as a username. +<P> + +<A NAME="IDX460"></A> +<DT><CODE>complete-variable (M-$)</CODE> +<DD><A NAME="IDX461"></A> +Attempt completion on the text before point, treating +it as a shell variable. +<P> + +<A NAME="IDX462"></A> +<DT><CODE>possible-variable-completions (C-x $)</CODE> +<DD><A NAME="IDX463"></A> +List the possible completions of the text before point, +treating it as a shell variable. +<P> + +<A NAME="IDX464"></A> +<DT><CODE>complete-hostname (M-@)</CODE> +<DD><A NAME="IDX465"></A> +Attempt completion on the text before point, treating +it as a hostname. +<P> + +<A NAME="IDX466"></A> +<DT><CODE>possible-hostname-completions (C-x @)</CODE> +<DD><A NAME="IDX467"></A> +List the possible completions of the text before point, +treating it as a hostname. +<P> + +<A NAME="IDX468"></A> +<DT><CODE>complete-command (M-!)</CODE> +<DD><A NAME="IDX469"></A> +Attempt completion on the text before point, treating +it as a command name. Command completion attempts to +match the text against aliases, reserved words, shell +functions, shell builtins, and finally executable filenames, +in that order. +<P> + +<A NAME="IDX470"></A> +<DT><CODE>possible-command-completions (C-x !)</CODE> +<DD><A NAME="IDX471"></A> +List the possible completions of the text before point, +treating it as a command name. +<P> + +<A NAME="IDX472"></A> +<DT><CODE>dynamic-complete-history (M-<KBD>TAB</KBD>)</CODE> +<DD><A NAME="IDX473"></A> +Attempt completion on the text before point, comparing +the text against lines from the history list for possible +completion matches. +<P> + +<A NAME="IDX474"></A> +<DT><CODE>dabbrev-expand ()</CODE> +<DD><A NAME="IDX475"></A> +Attempt menu completion on the text before point, comparing +the text against lines from the history list for possible +completion matches. +<P> + +<A NAME="IDX476"></A> +<DT><CODE>complete-into-braces (M-{)</CODE> +<DD><A NAME="IDX477"></A> +Perform filename completion and insert the list of possible completions +enclosed within braces so the list is available to the shell +(see section <A HREF="bashref.html#SEC29">3.5.1 Brace Expansion</A>). +<P> + +</DL> +<P> + +<A NAME="Keyboard Macros"></A> +<HR SIZE="6"> +<A NAME="SEC114"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC113"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC115"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC115"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC107"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC116"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 8.4.7 Keyboard Macros </H3> +<!--docid::SEC114::--> +<DL COMPACT> + +<A NAME="IDX478"></A> +<DT><CODE>start-kbd-macro (C-x ()</CODE> +<DD><A NAME="IDX479"></A> +Begin saving the characters typed into the current keyboard macro. +<P> + +<A NAME="IDX480"></A> +<DT><CODE>end-kbd-macro (C-x ))</CODE> +<DD><A NAME="IDX481"></A> +Stop saving the characters typed into the current keyboard macro +and save the definition. +<P> + +<A NAME="IDX482"></A> +<DT><CODE>call-last-kbd-macro (C-x e)</CODE> +<DD><A NAME="IDX483"></A> +Re-execute the last keyboard macro defined, by making the characters +in the macro appear as if typed at the keyboard. +<P> + +</DL> +<P> + +<A NAME="Miscellaneous Commands"></A> +<HR SIZE="6"> +<A NAME="SEC115"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC114"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC116"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC116"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC107"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC116"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 8.4.8 Some Miscellaneous Commands </H3> +<!--docid::SEC115::--> +<DL COMPACT> + +<A NAME="IDX484"></A> +<DT><CODE>re-read-init-file (C-x C-r)</CODE> +<DD><A NAME="IDX485"></A> +Read in the contents of the <VAR>inputrc</VAR> file, and incorporate +any bindings or variable assignments found there. +<P> + +<A NAME="IDX486"></A> +<DT><CODE>abort (C-g)</CODE> +<DD><A NAME="IDX487"></A> +Abort the current editing command and +ring the terminal's bell (subject to the setting of +<CODE>bell-style</CODE>). +<P> + +<A NAME="IDX488"></A> +<DT><CODE>do-uppercase-version (M-a, M-b, M-<VAR>x</VAR>, <small>...</small>)</CODE> +<DD><A NAME="IDX489"></A> +If the metafied character <VAR>x</VAR> is lowercase, run the command +that is bound to the corresponding uppercase character. +<P> + +<A NAME="IDX490"></A> +<DT><CODE>prefix-meta (<KBD>ESC</KBD>)</CODE> +<DD><A NAME="IDX491"></A> +Metafy the next character typed. This is for keyboards +without a meta key. Typing <SAMP>`<KBD>ESC</KBD> f'</SAMP> is equivalent to typing +<KBD>M-f</KBD>. +<P> + +<A NAME="IDX492"></A> +<DT><CODE>undo (C-_ or C-x C-u)</CODE> +<DD><A NAME="IDX493"></A> +Incremental undo, separately remembered for each line. +<P> + +<A NAME="IDX494"></A> +<DT><CODE>revert-line (M-r)</CODE> +<DD><A NAME="IDX495"></A> +Undo all changes made to this line. This is like executing the <CODE>undo</CODE> +command enough times to get back to the beginning. +<P> + +<A NAME="IDX496"></A> +<DT><CODE>tilde-expand (M-&)</CODE> +<DD><A NAME="IDX497"></A> +Perform tilde expansion on the current word. +<P> + +<A NAME="IDX498"></A> +<DT><CODE>set-mark (C-@)</CODE> +<DD><A NAME="IDX499"></A> +Set the mark to the point. If a +numeric argument is supplied, the mark is set to that position. +<P> + +<A NAME="IDX500"></A> +<DT><CODE>exchange-point-and-mark (C-x C-x)</CODE> +<DD><A NAME="IDX501"></A> +Swap the point with the mark. The current cursor position is set to +the saved position, and the old cursor position is saved as the mark. +<P> + +<A NAME="IDX502"></A> +<DT><CODE>character-search (C-])</CODE> +<DD><A NAME="IDX503"></A> +A character is read and point is moved to the next occurrence of that +character. A negative count searches for previous occurrences. +<P> + +<A NAME="IDX504"></A> +<DT><CODE>character-search-backward (M-C-])</CODE> +<DD><A NAME="IDX505"></A> +A character is read and point is moved to the previous occurrence +of that character. A negative count searches for subsequent +occurrences. +<P> + +<A NAME="IDX506"></A> +<DT><CODE>skip-csi-sequence ()</CODE> +<DD><A NAME="IDX507"></A> +Read enough characters to consume a multi-key sequence such as those +defined for keys like Home and End. Such sequences begin with a +Control Sequence Indicator (CSI), usually ESC-[. If this sequence is +bound to "\e[", keys producing such sequences will have no effect +unless explicitly bound to a readline command, instead of inserting +stray characters into the editing buffer. This is unbound by default, +but usually bound to ESC-[. +<P> + +<A NAME="IDX508"></A> +<DT><CODE>insert-comment (M-#)</CODE> +<DD><A NAME="IDX509"></A> +Without a numeric argument, the value of the <CODE>comment-begin</CODE> +variable is inserted at the beginning of the current line. +If a numeric argument is supplied, this command acts as a toggle: if +the characters at the beginning of the line do not match the value +of <CODE>comment-begin</CODE>, the value is inserted, otherwise +the characters in <CODE>comment-begin</CODE> are deleted from the beginning of +the line. +In either case, the line is accepted as if a newline had been typed. +The default value of <CODE>comment-begin</CODE> causes this command +to make the current line a shell comment. +If a numeric argument causes the comment character to be removed, the line +will be executed by the shell. +<P> + +<A NAME="IDX510"></A> +<DT><CODE>dump-functions ()</CODE> +<DD><A NAME="IDX511"></A> +Print all of the functions and their key bindings to the +Readline output stream. If a numeric argument is supplied, +the output is formatted in such a way that it can be made part +of an <VAR>inputrc</VAR> file. This command is unbound by default. +<P> + +<A NAME="IDX512"></A> +<DT><CODE>dump-variables ()</CODE> +<DD><A NAME="IDX513"></A> +Print all of the settable variables and their values to the +Readline output stream. If a numeric argument is supplied, +the output is formatted in such a way that it can be made part +of an <VAR>inputrc</VAR> file. This command is unbound by default. +<P> + +<A NAME="IDX514"></A> +<DT><CODE>dump-macros ()</CODE> +<DD><A NAME="IDX515"></A> +Print all of the Readline key sequences bound to macros and the +strings they output. If a numeric argument is supplied, +the output is formatted in such a way that it can be made part +of an <VAR>inputrc</VAR> file. This command is unbound by default. +<P> + +<A NAME="IDX516"></A> +<DT><CODE>glob-complete-word (M-g)</CODE> +<DD><A NAME="IDX517"></A> +The word before point is treated as a pattern for pathname expansion, +with an asterisk implicitly appended. This pattern is used to +generate a list of matching file names for possible completions. +<P> + +<A NAME="IDX518"></A> +<DT><CODE>glob-expand-word (C-x *)</CODE> +<DD><A NAME="IDX519"></A> +The word before point is treated as a pattern for pathname expansion, +and the list of matching file names is inserted, replacing the word. +If a numeric argument is supplied, a <SAMP>`*'</SAMP> is appended before +pathname expansion. +<P> + +<A NAME="IDX520"></A> +<DT><CODE>glob-list-expansions (C-x g)</CODE> +<DD><A NAME="IDX521"></A> +The list of expansions that would have been generated by +<CODE>glob-expand-word</CODE> is displayed, and the line is redrawn. +If a numeric argument is supplied, a <SAMP>`*'</SAMP> is appended before +pathname expansion. +<P> + +<A NAME="IDX522"></A> +<DT><CODE>display-shell-version (C-x C-v)</CODE> +<DD><A NAME="IDX523"></A> +Display version information about the current instance of Bash. +<P> + +<A NAME="IDX524"></A> +<DT><CODE>shell-expand-line (M-C-e)</CODE> +<DD><A NAME="IDX525"></A> +Expand the line as the shell does. +This performs alias and history expansion as well as all of the shell +word expansions (see section <A HREF="bashref.html#SEC28">3.5 Shell Expansions</A>). +<P> + +<A NAME="IDX526"></A> +<DT><CODE>history-expand-line (M-^)</CODE> +<DD><A NAME="IDX527"></A> +Perform history expansion on the current line. +<P> + +<A NAME="IDX528"></A> +<DT><CODE>magic-space ()</CODE> +<DD><A NAME="IDX529"></A> +Perform history expansion on the current line and insert a space +(see section <A HREF="bashref.html#SEC122">9.3 History Expansion</A>). +<P> + +<A NAME="IDX530"></A> +<DT><CODE>alias-expand-line ()</CODE> +<DD><A NAME="IDX531"></A> +Perform alias expansion on the current line (see section <A HREF="bashref.html#SEC84">6.6 Aliases</A>). +<P> + +<A NAME="IDX532"></A> +<DT><CODE>history-and-alias-expand-line ()</CODE> +<DD><A NAME="IDX533"></A> +Perform history and alias expansion on the current line. +<P> + +<A NAME="IDX534"></A> +<DT><CODE>insert-last-argument (M-. or M-_)</CODE> +<DD><A NAME="IDX535"></A> +A synonym for <CODE>yank-last-arg</CODE>. +<P> + +<A NAME="IDX536"></A> +<DT><CODE>operate-and-get-next (C-o)</CODE> +<DD><A NAME="IDX537"></A> +Accept the current line for execution and fetch the next line +relative to the current line from the history for editing. Any +argument is ignored. +<P> + +<A NAME="IDX538"></A> +<DT><CODE>edit-and-execute-command (C-xC-e)</CODE> +<DD><A NAME="IDX539"></A> +Invoke an editor on the current command line, and execute the result as shell +commands. +Bash attempts to invoke +<CODE>$VISUAL</CODE>, <CODE>$EDITOR</CODE>, and <CODE>emacs</CODE> +as the editor, in that order. +<P> + +</DL> +<P> + +<A NAME="Readline vi Mode"></A> +<HR SIZE="6"> +<A NAME="SEC116"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC115"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC117"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC117"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC95"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC119"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H2> 8.5 Readline vi Mode </H2> +<!--docid::SEC116::--> +<P> + +While the Readline library does not have a full set of <CODE>vi</CODE> +editing functions, it does contain enough to allow simple editing +of the line. The Readline <CODE>vi</CODE> mode behaves as specified in +the POSIX 1003.2 standard. +</P><P> + +In order to switch interactively between <CODE>emacs</CODE> and <CODE>vi</CODE> +editing modes, use the <SAMP>`set -o emacs'</SAMP> and <SAMP>`set -o vi'</SAMP> +commands (see section <A HREF="bashref.html#SEC62">4.3.1 The Set Builtin</A>). +The Readline default is <CODE>emacs</CODE> mode. +</P><P> + +When you enter a line in <CODE>vi</CODE> mode, you are already placed in +`insertion' mode, as if you had typed an <SAMP>`i'</SAMP>. Pressing <KBD>ESC</KBD> +switches you into `command' mode, where you can edit the text of the +line with the standard <CODE>vi</CODE> movement keys, move to previous +history lines with <SAMP>`k'</SAMP> and subsequent lines with <SAMP>`j'</SAMP>, and +so forth. +</P><P> + +<A NAME="Programmable Completion"></A> +<HR SIZE="6"> +<A NAME="SEC117"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC116"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC118"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC118"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC95"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC119"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H2> 8.6 Programmable Completion </H2> +<!--docid::SEC117::--> +<P> + +When word completion is attempted for an argument to a command for +which a completion specification (a <VAR>compspec</VAR>) has been defined +using the <CODE>complete</CODE> builtin (see section <A HREF="bashref.html#SEC118">8.7 Programmable Completion Builtins</A>), +the programmable completion facilities are invoked. +</P><P> + +First, the command name is identified. +If a compspec has been defined for that command, the +compspec is used to generate the list of possible completions for the word. +If the command word is the empty string (completion attempted at the +beginning of an empty line), any compspec defined with +the <SAMP>`-E'</SAMP> option to <CODE>complete</CODE> is used. +If the command word is a full pathname, a compspec for the full +pathname is searched for first. +If no compspec is found for the full pathname, an attempt is made to +find a compspec for the portion following the final slash. +If those searches do not result in a compspec, any compspec defined with +the <SAMP>`-D'</SAMP> option to <CODE>complete</CODE> is used as the default. +</P><P> + +Once a compspec has been found, it is used to generate the list of +matching words. +If a compspec is not found, the default Bash completion +described above (see section <A HREF="bashref.html#SEC113">8.4.6 Letting Readline Type For You</A>) is performed. +</P><P> + +First, the actions specified by the compspec are used. +Only matches which are prefixed by the word being completed are +returned. +When the <SAMP>`-f'</SAMP> or <SAMP>`-d'</SAMP> option is used for filename or +directory name completion, the shell variable <CODE>FIGNORE</CODE> is +used to filter the matches. +See section <A HREF="bashref.html#SEC67">5.2 Bash Variables</A>, for a description of <CODE>FIGNORE</CODE>. +</P><P> + +Any completions specified by a filename expansion pattern to the +<SAMP>`-G'</SAMP> option are generated next. +The words generated by the pattern need not match the word being completed. +The <CODE>GLOBIGNORE</CODE> shell variable is not used to filter the matches, +but the <CODE>FIGNORE</CODE> shell variable is used. +</P><P> + +Next, the string specified as the argument to the <SAMP>`-W'</SAMP> option +is considered. +The string is first split using the characters in the <CODE>IFS</CODE> +special variable as delimiters. +Shell quoting is honored. +Each word is then expanded using +brace expansion, tilde expansion, parameter and variable expansion, +command substitution, and arithmetic expansion, +as described above (see section <A HREF="bashref.html#SEC28">3.5 Shell Expansions</A>). +The results are split using the rules described above +(see section <A HREF="bashref.html#SEC35">3.5.7 Word Splitting</A>). +The results of the expansion are prefix-matched against the word being +completed, and the matching words become the possible completions. +</P><P> + +After these matches have been generated, any shell function or command +specified with the <SAMP>`-F'</SAMP> and <SAMP>`-C'</SAMP> options is invoked. +When the command or function is invoked, the <CODE>COMP_LINE</CODE>, +<CODE>COMP_POINT</CODE>, <CODE>COMP_KEY</CODE>, and <CODE>COMP_TYPE</CODE> variables are +assigned values as described above (see section <A HREF="bashref.html#SEC67">5.2 Bash Variables</A>). +If a shell function is being invoked, the <CODE>COMP_WORDS</CODE> and +<CODE>COMP_CWORD</CODE> variables are also set. +When the function or command is invoked, the first argument is the +name of the command whose arguments are being completed, the +second argument is the word being completed, and the third argument +is the word preceding the word being completed on the current command line. +No filtering of the generated completions against the word being completed +is performed; the function or command has complete freedom in generating +the matches. +</P><P> + +Any function specified with <SAMP>`-F'</SAMP> is invoked first. +The function may use any of the shell facilities, including the +<CODE>compgen</CODE> and <CODE>compopt</CODE> builtins described below +(see section <A HREF="bashref.html#SEC118">8.7 Programmable Completion Builtins</A>), to generate the matches. +It must put the possible completions in the <CODE>COMPREPLY</CODE> array +variable. +</P><P> + +Next, any command specified with the <SAMP>`-C'</SAMP> option is invoked +in an environment equivalent to command substitution. +It should print a list of completions, one per line, to +the standard output. +Backslash may be used to escape a newline, if necessary. +</P><P> + +After all of the possible completions are generated, any filter +specified with the <SAMP>`-X'</SAMP> option is applied to the list. +The filter is a pattern as used for pathname expansion; a <SAMP>`&'</SAMP> +in the pattern is replaced with the text of the word being completed. +A literal <SAMP>`&'</SAMP> may be escaped with a backslash; the backslash +is removed before attempting a match. +Any completion that matches the pattern will be removed from the list. +A leading <SAMP>`!'</SAMP> negates the pattern; in this case any completion +not matching the pattern will be removed. +</P><P> + +Finally, any prefix and suffix specified with the <SAMP>`-P'</SAMP> and <SAMP>`-S'</SAMP> +options are added to each member of the completion list, and the result is +returned to the Readline completion code as the list of possible +completions. +</P><P> + +If the previously-applied actions do not generate any matches, and the +<SAMP>`-o dirnames'</SAMP> option was supplied to <CODE>complete</CODE> when the +compspec was defined, directory name completion is attempted. +</P><P> + +If the <SAMP>`-o plusdirs'</SAMP> option was supplied to <CODE>complete</CODE> when +the compspec was defined, directory name completion is attempted and any +matches are added to the results of the other actions. +</P><P> + +By default, if a compspec is found, whatever it generates is returned to +the completion code as the full set of possible completions. +The default Bash completions are not attempted, and the Readline default +of filename completion is disabled. +If the <SAMP>`-o bashdefault'</SAMP> option was supplied to <CODE>complete</CODE> when +the compspec was defined, the default Bash completions are attempted +if the compspec generates no matches. +If the <SAMP>`-o default'</SAMP> option was supplied to <CODE>complete</CODE> when the +compspec was defined, Readline's default completion will be performed +if the compspec (and, if attempted, the default Bash completions) +generate no matches. +</P><P> + +When a compspec indicates that directory name completion is desired, +the programmable completion functions force Readline to append a slash +to completed names which are symbolic links to directories, subject to +the value of the <VAR>mark-directories</VAR> Readline variable, regardless +of the setting of the <VAR>mark-symlinked-directories</VAR> Readline variable. +</P><P> + +There is some support for dynamically modifying completions. This is +most useful when used in combination with a default completion specified +with <SAMP>`-D'</SAMP>. It's possible for shell functions executed as completion +handlers to indicate that completion should be retried by returning an +exit status of 124. If a shell function returns 124, and changes +the compspec associated with the command on which completion is being +attempted (supplied as the first argument when the function is executed), +programmable completion restarts from the beginning, with an +attempt to find a compspec for that command. This allows a set of +completions to be built dynamically as completion is attempted, rather than +being loaded all at once. +</P><P> + +For instance, assuming that there is a library of compspecs, each kept in a +file corresponding to the name of the command, the following default +completion function would load completions dynamically: +</P><P> + +<TABLE><tr><td> </td><td class=example><pre>_completion_loader() +{ + . "/etc/bash_completion.d/$1.sh" >/dev/null 2>&1 && return 124 +} +complete -D -F _completion_loader +</pre></td></tr></table></P><P> + +<A NAME="Programmable Completion Builtins"></A> +<HR SIZE="6"> +<A NAME="SEC118"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC117"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC119"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC95"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC95"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC119"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H2> 8.7 Programmable Completion Builtins </H2> +<!--docid::SEC118::--> +<P> + +Two builtin commands are available to manipulate the programmable completion +facilities. +</P><P> + +<DL COMPACT> +<DT><CODE>compgen</CODE> +<DD><A NAME="IDX540"></A> +<TABLE><tr><td> </td><td class=example><pre><CODE>compgen [<VAR>option</VAR>] [<VAR>word</VAR>]</CODE> +</pre></td></tr></table><P> + +Generate possible completion matches for <VAR>word</VAR> according to +the <VAR>option</VAR>s, which may be any option accepted by the +<CODE>complete</CODE> +builtin with the exception of <SAMP>`-p'</SAMP> and <SAMP>`-r'</SAMP>, and write +the matches to the standard output. +When using the <SAMP>`-F'</SAMP> or <SAMP>`-C'</SAMP> options, the various shell variables +set by the programmable completion facilities, while available, will not +have useful values. +</P><P> + +The matches will be generated in the same way as if the programmable +completion code had generated them directly from a completion specification +with the same flags. +If <VAR>word</VAR> is specified, only those completions matching <VAR>word</VAR> +will be displayed. +</P><P> + +The return value is true unless an invalid option is supplied, or no +matches were generated. +</P><P> + +<DT><CODE>complete</CODE> +<DD><A NAME="IDX541"></A> +<TABLE><tr><td> </td><td class=example><pre><CODE>complete [-abcdefgjksuv] [-o <VAR>comp-option</VAR>] [-DE] [-A <VAR>action</VAR>] [-G <VAR>globpat</VAR>] [-W <VAR>wordlist</VAR>] +[-F <VAR>function</VAR>] [-C <VAR>command</VAR>] [-X <VAR>filterpat</VAR>] +[-P <VAR>prefix</VAR>] [-S <VAR>suffix</VAR>] <VAR>name</VAR> [<VAR>name</VAR> <small>...</small>]</CODE> +<CODE>complete -pr [-DE] [<VAR>name</VAR> <small>...</small>]</CODE> +</pre></td></tr></table><P> + +Specify how arguments to each <VAR>name</VAR> should be completed. +If the <SAMP>`-p'</SAMP> option is supplied, or if no options are supplied, existing +completion specifications are printed in a way that allows them to be +reused as input. +The <SAMP>`-r'</SAMP> option removes a completion specification for +each <VAR>name</VAR>, or, if no <VAR>name</VAR>s are supplied, all +completion specifications. +The <SAMP>`-D'</SAMP> option indicates that the remaining options and actions should +apply to the "default" command completion; that is, completion attempted +on a command for which no completion has previously been defined. +The <SAMP>`-E'</SAMP> option indicates that the remaining options and actions should +apply to "empty" command completion; that is, completion attempted on a +blank line. +</P><P> + +The process of applying these completion specifications when word completion +is attempted is described above (see section <A HREF="bashref.html#SEC117">8.6 Programmable Completion</A>). The +<SAMP>`-D'</SAMP> option takes precedence over <SAMP>`-E'</SAMP>. +</P><P> + +Other options, if specified, have the following meanings. +The arguments to the <SAMP>`-G'</SAMP>, <SAMP>`-W'</SAMP>, and <SAMP>`-X'</SAMP> options +(and, if necessary, the <SAMP>`-P'</SAMP> and <SAMP>`-S'</SAMP> options) +should be quoted to protect them from expansion before the +<CODE>complete</CODE> builtin is invoked. +</P><P> + +<DL COMPACT> +<DT><CODE>-o <VAR>comp-option</VAR></CODE> +<DD>The <VAR>comp-option</VAR> controls several aspects of the compspec's behavior +beyond the simple generation of completions. +<VAR>comp-option</VAR> may be one of: +<P> + +<DL COMPACT> + +<DT><CODE>bashdefault</CODE> +<DD>Perform the rest of the default Bash completions if the compspec +generates no matches. +<P> + +<DT><CODE>default</CODE> +<DD>Use Readline's default filename completion if the compspec generates +no matches. +<P> + +<DT><CODE>dirnames</CODE> +<DD>Perform directory name completion if the compspec generates no matches. +<P> + +<DT><CODE>filenames</CODE> +<DD>Tell Readline that the compspec generates filenames, so it can perform any +filename-specific processing (like adding a slash to directory names +quoting special characters, or suppressing trailing spaces). +This option is intended to be used with shell functions specified +with <SAMP>`-F'</SAMP>. +<P> + +<DT><CODE>nospace</CODE> +<DD>Tell Readline not to append a space (the default) to words completed at +the end of the line. +<P> + +<DT><CODE>plusdirs</CODE> +<DD>After any matches defined by the compspec are generated, +directory name completion is attempted and any +matches are added to the results of the other actions. +<P> + +</DL> +<P> + +<DT><CODE>-A <VAR>action</VAR></CODE> +<DD>The <VAR>action</VAR> may be one of the following to generate a list of possible +completions: +<P> + +<DL COMPACT> +<DT><CODE>alias</CODE> +<DD>Alias names. May also be specified as <SAMP>`-a'</SAMP>. +<P> + +<DT><CODE>arrayvar</CODE> +<DD>Array variable names. +<P> + +<DT><CODE>binding</CODE> +<DD>Readline key binding names (see section <A HREF="bashref.html#SEC107">8.4 Bindable Readline Commands</A>). +<P> + +<DT><CODE>builtin</CODE> +<DD>Names of shell builtin commands. May also be specified as <SAMP>`-b'</SAMP>. +<P> + +<DT><CODE>command</CODE> +<DD>Command names. May also be specified as <SAMP>`-c'</SAMP>. +<P> + +<DT><CODE>directory</CODE> +<DD>Directory names. May also be specified as <SAMP>`-d'</SAMP>. +<P> + +<DT><CODE>disabled</CODE> +<DD>Names of disabled shell builtins. +<P> + +<DT><CODE>enabled</CODE> +<DD>Names of enabled shell builtins. +<P> + +<DT><CODE>export</CODE> +<DD>Names of exported shell variables. May also be specified as <SAMP>`-e'</SAMP>. +<P> + +<DT><CODE>file</CODE> +<DD>File names. May also be specified as <SAMP>`-f'</SAMP>. +<P> + +<DT><CODE>function</CODE> +<DD>Names of shell functions. +<P> + +<DT><CODE>group</CODE> +<DD>Group names. May also be specified as <SAMP>`-g'</SAMP>. +<P> + +<DT><CODE>helptopic</CODE> +<DD>Help topics as accepted by the <CODE>help</CODE> builtin (see section <A HREF="bashref.html#SEC60">4.2 Bash Builtin Commands</A>). +<P> + +<DT><CODE>hostname</CODE> +<DD>Hostnames, as taken from the file specified by the +<CODE>HOSTFILE</CODE> shell variable (see section <A HREF="bashref.html#SEC67">5.2 Bash Variables</A>). +<P> + +<DT><CODE>job</CODE> +<DD>Job names, if job control is active. May also be specified as <SAMP>`-j'</SAMP>. +<P> + +<DT><CODE>keyword</CODE> +<DD>Shell reserved words. May also be specified as <SAMP>`-k'</SAMP>. +<P> + +<DT><CODE>running</CODE> +<DD>Names of running jobs, if job control is active. +<P> + +<DT><CODE>service</CODE> +<DD>Service names. May also be specified as <SAMP>`-s'</SAMP>. +<P> + +<DT><CODE>setopt</CODE> +<DD>Valid arguments for the <SAMP>`-o'</SAMP> option to the <CODE>set</CODE> builtin +(see section <A HREF="bashref.html#SEC62">4.3.1 The Set Builtin</A>). +<P> + +<DT><CODE>shopt</CODE> +<DD>Shell option names as accepted by the <CODE>shopt</CODE> builtin +(see section <A HREF="bashref.html#SEC60">4.2 Bash Builtin Commands</A>). +<P> + +<DT><CODE>signal</CODE> +<DD>Signal names. +<P> + +<DT><CODE>stopped</CODE> +<DD>Names of stopped jobs, if job control is active. +<P> + +<DT><CODE>user</CODE> +<DD>User names. May also be specified as <SAMP>`-u'</SAMP>. +<P> + +<DT><CODE>variable</CODE> +<DD>Names of all shell variables. May also be specified as <SAMP>`-v'</SAMP>. +</DL> +<P> + +<DT><CODE>-G <VAR>globpat</VAR></CODE> +<DD>The filename expansion pattern <VAR>globpat</VAR> is expanded to generate +the possible completions. +<P> + +<DT><CODE>-W <VAR>wordlist</VAR></CODE> +<DD>The <VAR>wordlist</VAR> is split using the characters in the +<CODE>IFS</CODE> special variable as delimiters, and each resultant word +is expanded. +The possible completions are the members of the resultant list which +match the word being completed. +<P> + +<DT><CODE>-C <VAR>command</VAR></CODE> +<DD><VAR>command</VAR> is executed in a subshell environment, and its output is +used as the possible completions. +<P> + +<DT><CODE>-F <VAR>function</VAR></CODE> +<DD>The shell function <VAR>function</VAR> is executed in the current shell +environment. +When it finishes, the possible completions are retrieved from the value +of the <CODE>COMPREPLY</CODE> array variable. +<P> + +<DT><CODE>-X <VAR>filterpat</VAR></CODE> +<DD><VAR>filterpat</VAR> is a pattern as used for filename expansion. +It is applied to the list of possible completions generated by the +preceding options and arguments, and each completion matching +<VAR>filterpat</VAR> is removed from the list. +A leading <SAMP>`!'</SAMP> in <VAR>filterpat</VAR> negates the pattern; in this +case, any completion not matching <VAR>filterpat</VAR> is removed. +<P> + +<DT><CODE>-P <VAR>prefix</VAR></CODE> +<DD><VAR>prefix</VAR> is added at the beginning of each possible completion +after all other options have been applied. +<P> + +<DT><CODE>-S <VAR>suffix</VAR></CODE> +<DD><VAR>suffix</VAR> is appended to each possible completion +after all other options have been applied. +</DL> +<P> + +The return value is true unless an invalid option is supplied, an option +other than <SAMP>`-p'</SAMP> or <SAMP>`-r'</SAMP> is supplied without a <VAR>name</VAR> +argument, an attempt is made to remove a completion specification for +a <VAR>name</VAR> for which no specification exists, or +an error occurs adding a completion specification. +</P><P> + +<DT><CODE>compopt</CODE> +<DD><A NAME="IDX542"></A> +<TABLE><tr><td> </td><td class=example><pre><CODE>compopt</CODE> [-o <VAR>option</VAR>] [-DE] [+o <VAR>option</VAR>] [<VAR>name</VAR>] +</pre></td></tr></table>Modify completion options for each <VAR>name</VAR> according to the +<VAR>option</VAR>s, or for the currently-execution completion if no <VAR>name</VAR>s +are supplied. +If no <VAR>option</VAR>s are given, display the completion options for each +<VAR>name</VAR> or the current completion. +The possible values of <VAR>option</VAR> are those valid for the <CODE>complete</CODE> +builtin described above. +The <SAMP>`-D'</SAMP> option indicates that the remaining options should +apply to the "default" command completion; that is, completion attempted +on a command for which no completion has previously been defined. +The <SAMP>`-E'</SAMP> option indicates that the remaining options should +apply to "empty" command completion; that is, completion attempted on a +blank line. +<P> + +The <SAMP>`-D'</SAMP> option takes precedence over <SAMP>`-E'</SAMP>. +</P><P> + +The return value is true unless an invalid option is supplied, an attempt +is made to modify the options for a <VAR>name</VAR> for which no completion +specification exists, or an output error occurs. +</P><P> + +</DL> +<P> + +<A NAME="IDX543"></A> +</P><P> + +<A NAME="Using History Interactively"></A> +<HR SIZE="6"> +<A NAME="SEC119"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC118"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC120"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[ << ]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC126"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H1> 9. Using History Interactively </H1> +<!--docid::SEC119::--> +<P> + +This chapter describes how to use the GNU History Library +interactively, from a user's standpoint. +It should be considered a user's guide. +For information on using the GNU History Library in other programs, +see the GNU Readline Library Manual. +</P><P> + +<BLOCKQUOTE><TABLE BORDER=0 CELLSPACING=0> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC120">9.1 Bash History Facilities</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">How Bash lets you manipulate your command + history.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC121">9.2 Bash History Builtins</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">The Bash builtin commands that manipulate + the command history.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC122">9.3 History Expansion</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">What it feels like using History as a user.</TD></TR> +</TABLE></BLOCKQUOTE> +<P> + +<A NAME="Bash History Facilities"></A> +<HR SIZE="6"> +<A NAME="SEC120"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC119"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC121"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[ << ]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC119"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC126"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H2> 9.1 Bash History Facilities </H2> +<!--docid::SEC120::--> +<P> + +When the <SAMP>`-o history'</SAMP> option to the <CODE>set</CODE> builtin +is enabled (see section <A HREF="bashref.html#SEC62">4.3.1 The Set Builtin</A>), +the shell provides access to the <EM>command history</EM>, +the list of commands previously typed. +The value of the <CODE>HISTSIZE</CODE> shell variable is used as the +number of commands to save in a history list. +The text of the last <CODE>$HISTSIZE</CODE> +commands (default 500) is saved. +The shell stores each command in the history list prior to +parameter and variable expansion +but after history expansion is performed, subject to the +values of the shell variables +<CODE>HISTIGNORE</CODE> and <CODE>HISTCONTROL</CODE>. +</P><P> + +When the shell starts up, the history is initialized from the +file named by the <CODE>HISTFILE</CODE> variable (default <TT>`~/.bash_history'</TT>). +The file named by the value of <CODE>HISTFILE</CODE> is truncated, if +necessary, to contain no more than the number of lines specified by +the value of the <CODE>HISTFILESIZE</CODE> variable. +When an interactive shell exits, the last +<CODE>$HISTSIZE</CODE> lines are copied from the history list to the file +named by <CODE>$HISTFILE</CODE>. +If the <CODE>histappend</CODE> shell option is set (see section <A HREF="bashref.html#SEC60">4.2 Bash Builtin Commands</A>), +the lines are appended to the history file, +otherwise the history file is overwritten. +If <CODE>HISTFILE</CODE> +is unset, or if the history file is unwritable, the history is +not saved. After saving the history, the history file is truncated +to contain no more than <CODE>$HISTFILESIZE</CODE> +lines. If <CODE>HISTFILESIZE</CODE> is not set, no truncation is performed. +</P><P> + +If the <CODE>HISTTIMEFORMAT</CODE> is set, the time stamp information +associated with each history entry is written to the history file, +marked with the history comment character. +When the history file is read, lines beginning with the history +comment character followed immediately by a digit are interpreted +as timestamps for the previous history line. +</P><P> + +The builtin command <CODE>fc</CODE> may be used to list or edit and re-execute +a portion of the history list. +The <CODE>history</CODE> builtin may be used to display or modify the history +list and manipulate the history file. +When using command-line editing, search commands +are available in each editing mode that provide access to the +history list (see section <A HREF="bashref.html#SEC109">8.4.2 Commands For Manipulating The History</A>). +</P><P> + +The shell allows control over which commands are saved on the history +list. The <CODE>HISTCONTROL</CODE> and <CODE>HISTIGNORE</CODE> +variables may be set to cause the shell to save only a subset of the +commands entered. +The <CODE>cmdhist</CODE> +shell option, if enabled, causes the shell to attempt to save each +line of a multi-line command in the same history entry, adding +semicolons where necessary to preserve syntactic correctness. +The <CODE>lithist</CODE> +shell option causes the shell to save the command with embedded newlines +instead of semicolons. +The <CODE>shopt</CODE> builtin is used to set these options. +See section <A HREF="bashref.html#SEC60">4.2 Bash Builtin Commands</A>, for a description of <CODE>shopt</CODE>. +</P><P> + +<A NAME="Bash History Builtins"></A> +<HR SIZE="6"> +<A NAME="SEC121"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC120"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC122"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC122"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC119"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC126"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H2> 9.2 Bash History Builtins </H2> +<!--docid::SEC121::--> +<P> + +Bash provides two builtin commands which manipulate the +history list and history file. +</P><P> + +<DL COMPACT> + +<DT><CODE>fc</CODE> +<DD><A NAME="IDX544"></A> +<TABLE><tr><td> </td><td class=example><pre><CODE>fc [-e <VAR>ename</VAR>] [-lnr] [<VAR>first</VAR>] [<VAR>last</VAR>]</CODE> +<CODE>fc -s [<VAR>pat</VAR>=<VAR>rep</VAR>] [<VAR>command</VAR>]</CODE> +</pre></td></tr></table><P> + +Fix Command. In the first form, a range of commands from <VAR>first</VAR> to +<VAR>last</VAR> is selected from the history list. Both <VAR>first</VAR> and +<VAR>last</VAR> may be specified as a string (to locate the most recent +command beginning with that string) or as a number (an index into the +history list, where a negative number is used as an offset from the +current command number). If <VAR>last</VAR> is not specified it is set to +<VAR>first</VAR>. If <VAR>first</VAR> is not specified it is set to the previous +command for editing and -16 for listing. If the <SAMP>`-l'</SAMP> flag is +given, the commands are listed on standard output. The <SAMP>`-n'</SAMP> flag +suppresses the command numbers when listing. The <SAMP>`-r'</SAMP> flag +reverses the order of the listing. Otherwise, the editor given by +<VAR>ename</VAR> is invoked on a file containing those commands. If +<VAR>ename</VAR> is not given, the value of the following variable expansion +is used: <CODE>${FCEDIT:-${EDITOR:-vi}}</CODE>. This says to use the +value of the <CODE>FCEDIT</CODE> variable if set, or the value of the +<CODE>EDITOR</CODE> variable if that is set, or <CODE>vi</CODE> if neither is set. +When editing is complete, the edited commands are echoed and executed. +</P><P> + +In the second form, <VAR>command</VAR> is re-executed after each instance +of <VAR>pat</VAR> in the selected command is replaced by <VAR>rep</VAR>. +</P><P> + +A useful alias to use with the <CODE>fc</CODE> command is <CODE>r='fc -s'</CODE>, so +that typing <SAMP>`r cc'</SAMP> runs the last command beginning with <CODE>cc</CODE> +and typing <SAMP>`r'</SAMP> re-executes the last command (see section <A HREF="bashref.html#SEC84">6.6 Aliases</A>). +</P><P> + +<DT><CODE>history</CODE> +<DD><A NAME="IDX545"></A> +<TABLE><tr><td> </td><td class=example><pre>history [<VAR>n</VAR>] +history -c +history -d <VAR>offset</VAR> +history [-anrw] [<VAR>filename</VAR>] +history -ps <VAR>arg</VAR> +</pre></td></tr></table><P> + +With no options, display the history list with line numbers. +Lines prefixed with a <SAMP>`*'</SAMP> have been modified. +An argument of <VAR>n</VAR> lists only the last <VAR>n</VAR> lines. +If the shell variable <CODE>HISTTIMEFORMAT</CODE> is set and not null, +it is used as a format string for <VAR>strftime</VAR> to display +the time stamp associated with each displayed history entry. +No intervening blank is printed between the formatted time stamp +and the history line. +</P><P> + +Options, if supplied, have the following meanings: +</P><P> + +<DL COMPACT> +<DT><CODE>-c</CODE> +<DD>Clear the history list. This may be combined +with the other options to replace the history list completely. +<P> + +<DT><CODE>-d <VAR>offset</VAR></CODE> +<DD>Delete the history entry at position <VAR>offset</VAR>. +<VAR>offset</VAR> should be specified as it appears when the history is +displayed. +<P> + +<DT><CODE>-a</CODE> +<DD>Append the new +history lines (history lines entered since the beginning of the +current Bash session) to the history file. +<P> + +<DT><CODE>-n</CODE> +<DD>Append the history lines not already read from the history file +to the current history list. These are lines appended to the history +file since the beginning of the current Bash session. +<P> + +<DT><CODE>-r</CODE> +<DD>Read the current history file and append its contents to +the history list. +<P> + +<DT><CODE>-w</CODE> +<DD>Write out the current history to the history file. +<P> + +<DT><CODE>-p</CODE> +<DD>Perform history substitution on the <VAR>arg</VAR>s and display the result +on the standard output, without storing the results in the history list. +<P> + +<DT><CODE>-s</CODE> +<DD>The <VAR>arg</VAR>s are added to the end of +the history list as a single entry. +<P> + +</DL> +<P> + +When any of the <SAMP>`-w'</SAMP>, <SAMP>`-r'</SAMP>, <SAMP>`-a'</SAMP>, or <SAMP>`-n'</SAMP> options is +used, if <VAR>filename</VAR> +is given, then it is used as the history file. If not, then +the value of the <CODE>HISTFILE</CODE> variable is used. +</P><P> + +</DL> +<P> + +<A NAME="History Interaction"></A> +<HR SIZE="6"> +<A NAME="SEC122"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC121"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC123"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[ << ]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC119"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC126"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H2> 9.3 History Expansion </H2> +<!--docid::SEC122::--> +<P> + +The History library provides a history expansion feature that is similar +to the history expansion provided by <CODE>csh</CODE>. This section +describes the syntax used to manipulate the history information. +</P><P> + +History expansions introduce words from the history list into +the input stream, making it easy to repeat commands, insert the +arguments to a previous command into the current input line, or +fix errors in previous commands quickly. +</P><P> + +History expansion takes place in two parts. The first is to determine +which line from the history list should be used during substitution. +The second is to select portions of that line for inclusion into the +current one. The line selected from the history is called the +<EM>event</EM>, and the portions of that line that are acted upon are +called <EM>words</EM>. Various <EM>modifiers</EM> are available to manipulate +the selected words. The line is broken into words in the same fashion +that Bash does, so that several words +surrounded by quotes are considered one word. +History expansions are introduced by the appearance of the +history expansion character, which is <SAMP>`!'</SAMP> by default. +Only <SAMP>`\'</SAMP> and <SAMP>`''</SAMP> may be used to escape the history expansion +character. +</P><P> + +Several shell options settable with the <CODE>shopt</CODE> +builtin (see section <A HREF="bashref.html#SEC60">4.2 Bash Builtin Commands</A>) may be used to tailor +the behavior of history expansion. If the +<CODE>histverify</CODE> shell option is enabled, and Readline +is being used, history substitutions are not immediately passed to +the shell parser. +Instead, the expanded line is reloaded into the Readline +editing buffer for further modification. +If Readline is being used, and the <CODE>histreedit</CODE> +shell option is enabled, a failed history expansion will be +reloaded into the Readline editing buffer for correction. +The <SAMP>`-p'</SAMP> option to the <CODE>history</CODE> builtin command +may be used to see what a history expansion will do before using it. +The <SAMP>`-s'</SAMP> option to the <CODE>history</CODE> builtin may be used to +add commands to the end of the history list without actually executing +them, so that they are available for subsequent recall. +This is most useful in conjunction with Readline. +</P><P> + +The shell allows control of the various characters used by the +history expansion mechanism with the <CODE>histchars</CODE> variable, +as explained above (see section <A HREF="bashref.html#SEC67">5.2 Bash Variables</A>). The shell uses +the history comment character to mark history timestamps when +writing the history file. +</P><P> + +<BLOCKQUOTE><TABLE BORDER=0 CELLSPACING=0> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC123">9.3.1 Event Designators</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">How to specify which history line to use.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC124">9.3.2 Word Designators</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Specifying which words are of interest.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC125">9.3.3 Modifiers</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Modifying the results of substitution.</TD></TR> +</TABLE></BLOCKQUOTE> +<P> + +<A NAME="Event Designators"></A> +<HR SIZE="6"> +<A NAME="SEC123"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC122"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC124"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[ << ]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC122"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC126"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 9.3.1 Event Designators </H3> +<!--docid::SEC123::--> +<P> + +An event designator is a reference to a command line entry in the +history list. +<A NAME="IDX546"></A> +</P><P> + +<DL COMPACT> + +<DT><CODE>!</CODE> +<DD>Start a history substitution, except when followed by a space, tab, +the end of the line, <SAMP>`='</SAMP> or <SAMP>`('</SAMP> (when the +<CODE>extglob</CODE> shell option is enabled using the <CODE>shopt</CODE> builtin). +<P> + +<DT><CODE>!<VAR>n</VAR></CODE> +<DD>Refer to command line <VAR>n</VAR>. +<P> + +<DT><CODE>!-<VAR>n</VAR></CODE> +<DD>Refer to the command <VAR>n</VAR> lines back. +<P> + +<DT><CODE>!!</CODE> +<DD>Refer to the previous command. This is a synonym for <SAMP>`!-1'</SAMP>. +<P> + +<DT><CODE>!<VAR>string</VAR></CODE> +<DD>Refer to the most recent command starting with <VAR>string</VAR>. +<P> + +<DT><CODE>!?<VAR>string</VAR>[?]</CODE> +<DD>Refer to the most recent command containing <VAR>string</VAR>. The trailing +<SAMP>`?'</SAMP> may be omitted if the <VAR>string</VAR> is followed immediately by +a newline. +<P> + +<DT><CODE>^<VAR>string1</VAR>^<VAR>string2</VAR>^</CODE> +<DD>Quick Substitution. Repeat the last command, replacing <VAR>string1</VAR> +with <VAR>string2</VAR>. Equivalent to +<CODE>!!:s/<VAR>string1</VAR>/<VAR>string2</VAR>/</CODE>. +<P> + +<DT><CODE>!#</CODE> +<DD>The entire command line typed so far. +<P> + +</DL> +<P> + +<A NAME="Word Designators"></A> +<HR SIZE="6"> +<A NAME="SEC124"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC123"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC125"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC125"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC122"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC126"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 9.3.2 Word Designators </H3> +<!--docid::SEC124::--> +<P> + +Word designators are used to select desired words from the event. +A <SAMP>`:'</SAMP> separates the event specification from the word designator. It +may be omitted if the word designator begins with a <SAMP>`^'</SAMP>, <SAMP>`$'</SAMP>, +<SAMP>`*'</SAMP>, <SAMP>`-'</SAMP>, or <SAMP>`%'</SAMP>. Words are numbered from the beginning +of the line, with the first word being denoted by 0 (zero). Words are +inserted into the current line separated by single spaces. +</P><P> + +For example, +</P><P> + +<DL COMPACT> +<DT><CODE>!!</CODE> +<DD>designates the preceding command. When you type this, the preceding +command is repeated in toto. +<P> + +<DT><CODE>!!:$</CODE> +<DD>designates the last argument of the preceding command. This may be +shortened to <CODE>!$</CODE>. +<P> + +<DT><CODE>!fi:2</CODE> +<DD>designates the second argument of the most recent command starting with +the letters <CODE>fi</CODE>. +</DL> +<P> + +Here are the word designators: + +<DL COMPACT> + +<DT><CODE>0 (zero)</CODE> +<DD>The <CODE>0</CODE>th word. For many applications, this is the command word. +<P> + +<DT><CODE><VAR>n</VAR></CODE> +<DD>The <VAR>n</VAR>th word. +<P> + +<DT><CODE>^</CODE> +<DD>The first argument; that is, word 1. +<P> + +<DT><CODE>$</CODE> +<DD>The last argument. +<P> + +<DT><CODE>%</CODE> +<DD>The word matched by the most recent <SAMP>`?<VAR>string</VAR>?'</SAMP> search. +<P> + +<DT><CODE><VAR>x</VAR>-<VAR>y</VAR></CODE> +<DD>A range of words; <SAMP>`-<VAR>y</VAR>'</SAMP> abbreviates <SAMP>`0-<VAR>y</VAR>'</SAMP>. +<P> + +<DT><CODE>*</CODE> +<DD>All of the words, except the <CODE>0</CODE>th. This is a synonym for <SAMP>`1-$'</SAMP>. +It is not an error to use <SAMP>`*'</SAMP> if there is just one word in the event; +the empty string is returned in that case. +<P> + +<DT><CODE><VAR>x</VAR>*</CODE> +<DD>Abbreviates <SAMP>`<VAR>x</VAR>-$'</SAMP> +<P> + +<DT><CODE><VAR>x</VAR>-</CODE> +<DD>Abbreviates <SAMP>`<VAR>x</VAR>-$'</SAMP> like <SAMP>`<VAR>x</VAR>*'</SAMP>, but omits the last word. +<P> + +</DL> +<P> + +If a word designator is supplied without an event specification, the +previous command is used as the event. +</P><P> + +<A NAME="Modifiers"></A> +<HR SIZE="6"> +<A NAME="SEC125"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC124"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC126"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[ << ]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC122"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC126"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H3> 9.3.3 Modifiers </H3> +<!--docid::SEC125::--> +<P> + +After the optional word designator, you can add a sequence of one or more +of the following modifiers, each preceded by a <SAMP>`:'</SAMP>. +</P><P> + +<DL COMPACT> + +<DT><CODE>h</CODE> +<DD>Remove a trailing pathname component, leaving only the head. +<P> + +<DT><CODE>t</CODE> +<DD>Remove all leading pathname components, leaving the tail. +<P> + +<DT><CODE>r</CODE> +<DD>Remove a trailing suffix of the form <SAMP>`.<VAR>suffix</VAR>'</SAMP>, leaving +the basename. +<P> + +<DT><CODE>e</CODE> +<DD>Remove all but the trailing suffix. +<P> + +<DT><CODE>p</CODE> +<DD>Print the new command but do not execute it. +<P> + +<DT><CODE>q</CODE> +<DD>Quote the substituted words, escaping further substitutions. +<P> + +<DT><CODE>x</CODE> +<DD>Quote the substituted words as with <SAMP>`q'</SAMP>, +but break into words at spaces, tabs, and newlines. +<P> + +<DT><CODE>s/<VAR>old</VAR>/<VAR>new</VAR>/</CODE> +<DD>Substitute <VAR>new</VAR> for the first occurrence of <VAR>old</VAR> in the +event line. Any delimiter may be used in place of <SAMP>`/'</SAMP>. +The delimiter may be quoted in <VAR>old</VAR> and <VAR>new</VAR> +with a single backslash. If <SAMP>`&'</SAMP> appears in <VAR>new</VAR>, +it is replaced by <VAR>old</VAR>. A single backslash will quote +the <SAMP>`&'</SAMP>. The final delimiter is optional if it is the last +character on the input line. +<P> + +<DT><CODE>&</CODE> +<DD>Repeat the previous substitution. +<P> + +<DT><CODE>g</CODE> +<DD><DT><CODE>a</CODE> +<DD>Cause changes to be applied over the entire event line. Used in +conjunction with <SAMP>`s'</SAMP>, as in <CODE>gs/<VAR>old</VAR>/<VAR>new</VAR>/</CODE>, +or with <SAMP>`&'</SAMP>. +<P> + +<DT><CODE>G</CODE> +<DD>Apply the following <SAMP>`s'</SAMP> modifier once to each word in the event. +<P> + +</DL> +<P> + +<A NAME="Installing Bash"></A> +<HR SIZE="6"> +<A NAME="SEC126"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC125"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC127"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC4"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC135"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H1> 10. Installing Bash </H1> +<!--docid::SEC126::--> +<P> + +This chapter provides basic instructions for installing Bash on +the various supported platforms. The distribution supports the +GNU operating systems, nearly every version of Unix, and several +non-Unix systems such as BeOS and Interix. +Other independent ports exist for +MS-DOS, OS/2, and Windows platforms. +</P><P> + +<BLOCKQUOTE><TABLE BORDER=0 CELLSPACING=0> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC127">10.1 Basic Installation</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Installation instructions.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC128">10.2 Compilers and Options</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">How to set special options for various + systems.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC129">10.3 Compiling For Multiple Architectures</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">How to compile Bash for more + than one kind of system from + the same source tree.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC130">10.4 Installation Names</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">How to set the various paths used by the installation.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC131">10.5 Specifying the System Type</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">How to configure Bash for a particular system.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC132">10.6 Sharing Defaults</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">How to share default configuration values among GNU + programs.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC133">10.7 Operation Controls</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Options recognized by the configuration program.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC134">10.8 Optional Features</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">How to enable and disable optional features when + building Bash.</TD></TR> +</TABLE></BLOCKQUOTE> +<P> + +<A NAME="Basic Installation"></A> +<HR SIZE="6"> +<A NAME="SEC127"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC126"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC128"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC126"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC126"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC135"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H2> 10.1 Basic Installation </H2> +<!--docid::SEC127::--> +<P> + +These are installation instructions for Bash. +</P><P> + +The simplest way to compile Bash is: +</P><P> + +<OL> +<LI> +<CODE>cd</CODE> to the directory containing the source code and type +<SAMP>`./configure'</SAMP> to configure Bash for your system. If you're +using <CODE>csh</CODE> on an old version of System V, you might need to +type <SAMP>`sh ./configure'</SAMP> instead to prevent <CODE>csh</CODE> from trying +to execute <CODE>configure</CODE> itself. +<P> + +Running <CODE>configure</CODE> takes some time. +While running, it prints messages telling which features it is +checking for. +</P><P> + +<LI> +Type <SAMP>`make'</SAMP> to compile Bash and build the <CODE>bashbug</CODE> bug +reporting script. +<P> + +<LI> +Optionally, type <SAMP>`make tests'</SAMP> to run the Bash test suite. +<P> + +<LI> +Type <SAMP>`make install'</SAMP> to install <CODE>bash</CODE> and <CODE>bashbug</CODE>. +This will also install the manual pages and Info file. +<P> + +</OL> +<P> + +The <CODE>configure</CODE> shell script attempts to guess correct +values for various system-dependent variables used during +compilation. It uses those values to create a <TT>`Makefile'</TT> in +each directory of the package (the top directory, the +<TT>`builtins'</TT>, <TT>`doc'</TT>, and <TT>`support'</TT> directories, +each directory under <TT>`lib'</TT>, and several others). It also creates a +<TT>`config.h'</TT> file containing system-dependent definitions. +Finally, it creates a shell script named <CODE>config.status</CODE> that you +can run in the future to recreate the current configuration, a +file <TT>`config.cache'</TT> that saves the results of its tests to +speed up reconfiguring, and a file <TT>`config.log'</TT> containing +compiler output (useful mainly for debugging <CODE>configure</CODE>). +If at some point +<TT>`config.cache'</TT> contains results you don't want to keep, you +may remove or edit it. +</P><P> + +To find out more about the options and arguments that the +<CODE>configure</CODE> script understands, type +</P><P> + +<TABLE><tr><td> </td><td class=example><pre>bash-2.04$ ./configure --help +</pre></td></tr></table></P><P> + +at the Bash prompt in your Bash source directory. +</P><P> + +If you need to do unusual things to compile Bash, please +try to figure out how <CODE>configure</CODE> could check whether or not +to do them, and mail diffs or instructions to +<A HREF="mailto:bash-maintainers@gnu.org">bash-maintainers@gnu.org</A> so they can be +considered for the next release. +</P><P> + +The file <TT>`configure.in'</TT> is used to create <CODE>configure</CODE> +by a program called Autoconf. You only need +<TT>`configure.in'</TT> if you want to change it or regenerate +<CODE>configure</CODE> using a newer version of Autoconf. If +you do this, make sure you are using Autoconf version 2.50 or +newer. +</P><P> + +You can remove the program binaries and object files from the +source code directory by typing <SAMP>`make clean'</SAMP>. To also remove the +files that <CODE>configure</CODE> created (so you can compile Bash for +a different kind of computer), type <SAMP>`make distclean'</SAMP>. +</P><P> + +<A NAME="Compilers and Options"></A> +<HR SIZE="6"> +<A NAME="SEC128"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC127"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC129"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC129"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC126"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC135"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H2> 10.2 Compilers and Options </H2> +<!--docid::SEC128::--> +<P> + +Some systems require unusual options for compilation or linking +that the <CODE>configure</CODE> script does not know about. You can +give <CODE>configure</CODE> initial values for variables by setting +them in the environment. Using a Bourne-compatible shell, you +can do that on the command line like this: +</P><P> + +<TABLE><tr><td> </td><td class=example><pre>CC=c89 CFLAGS=-O2 LIBS=-lposix ./configure +</pre></td></tr></table></P><P> + +On systems that have the <CODE>env</CODE> program, you can do it like this: +</P><P> + +<TABLE><tr><td> </td><td class=example><pre>env CPPFLAGS=-I/usr/local/include LDFLAGS=-s ./configure +</pre></td></tr></table></P><P> + +The configuration process uses GCC to build Bash if it +is available. +</P><P> + +<A NAME="Compiling For Multiple Architectures"></A> +<HR SIZE="6"> +<A NAME="SEC129"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC128"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC130"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC130"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC126"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC135"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H2> 10.3 Compiling For Multiple Architectures </H2> +<!--docid::SEC129::--> +<P> + +You can compile Bash for more than one kind of computer at the +same time, by placing the object files for each architecture in their +own directory. To do this, you must use a version of <CODE>make</CODE> that +supports the <CODE>VPATH</CODE> variable, such as GNU <CODE>make</CODE>. +<CODE>cd</CODE> to the +directory where you want the object files and executables to go and run +the <CODE>configure</CODE> script from the source directory. You may need to +supply the <SAMP>`--srcdir=PATH'</SAMP> argument to tell <CODE>configure</CODE> where the +source files are. <CODE>configure</CODE> automatically checks for the +source code in the directory that <CODE>configure</CODE> is in and in `..'. +</P><P> + +If you have to use a <CODE>make</CODE> that does not supports the <CODE>VPATH</CODE> +variable, you can compile Bash for one architecture at a +time in the source code directory. After you have installed +Bash for one architecture, use <SAMP>`make distclean'</SAMP> before +reconfiguring for another architecture. +</P><P> + +Alternatively, if your system supports symbolic links, you can use the +<TT>`support/mkclone'</TT> script to create a build tree which has +symbolic links back to each file in the source directory. Here's an +example that creates a build directory in the current directory from a +source directory <TT>`/usr/gnu/src/bash-2.0'</TT>: +</P><P> + +<TABLE><tr><td> </td><td class=example><pre>bash /usr/gnu/src/bash-2.0/support/mkclone -s /usr/gnu/src/bash-2.0 . +</pre></td></tr></table></P><P> + +The <CODE>mkclone</CODE> script requires Bash, so you must have already built +Bash for at least one architecture before you can create build +directories for other architectures. +</P><P> + +<A NAME="Installation Names"></A> +<HR SIZE="6"> +<A NAME="SEC130"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC129"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC131"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC131"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC126"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC135"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H2> 10.4 Installation Names </H2> +<!--docid::SEC130::--> +<P> + +By default, <SAMP>`make install'</SAMP> will install into +<TT>`/usr/local/bin'</TT>, <TT>`/usr/local/man'</TT>, etc. You can +specify an installation prefix other than <TT>`/usr/local'</TT> by +giving <CODE>configure</CODE> the option <SAMP>`--prefix=<VAR>PATH</VAR>'</SAMP>, +or by specifying a value for the <CODE>DESTDIR</CODE> <SAMP>`make'</SAMP> +variable when running <SAMP>`make install'</SAMP>. +</P><P> + +You can specify separate installation prefixes for +architecture-specific files and architecture-independent files. +If you give <CODE>configure</CODE> the option +<SAMP>`--exec-prefix=<VAR>PATH</VAR>'</SAMP>, <SAMP>`make install'</SAMP> will use +<VAR>PATH</VAR> as the prefix for installing programs and libraries. +Documentation and other data files will still use the regular prefix. +</P><P> + +<A NAME="Specifying the System Type"></A> +<HR SIZE="6"> +<A NAME="SEC131"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC130"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC132"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC132"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC126"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC135"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H2> 10.5 Specifying the System Type </H2> +<!--docid::SEC131::--> +<P> + +There may be some features <CODE>configure</CODE> can not figure out +automatically, but need to determine by the type of host Bash +will run on. Usually <CODE>configure</CODE> can figure that +out, but if it prints a message saying it can not guess the host +type, give it the <SAMP>`--host=TYPE'</SAMP> option. <SAMP>`TYPE'</SAMP> can +either be a short name for the system type, such as <SAMP>`sun4'</SAMP>, +or a canonical name with three fields: <SAMP>`CPU-COMPANY-SYSTEM'</SAMP> +(e.g., <SAMP>`i386-unknown-freebsd4.2'</SAMP>). +</P><P> + +See the file <TT>`support/config.sub'</TT> for the possible +values of each field. +</P><P> + +<A NAME="Sharing Defaults"></A> +<HR SIZE="6"> +<A NAME="SEC132"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC131"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC133"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC133"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC126"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC135"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H2> 10.6 Sharing Defaults </H2> +<!--docid::SEC132::--> +<P> + +If you want to set default values for <CODE>configure</CODE> scripts to +share, you can create a site shell script called +<CODE>config.site</CODE> that gives default values for variables like +<CODE>CC</CODE>, <CODE>cache_file</CODE>, and <CODE>prefix</CODE>. <CODE>configure</CODE> +looks for <TT>`PREFIX/share/config.site'</TT> if it exists, then +<TT>`PREFIX/etc/config.site'</TT> if it exists. Or, you can set the +<CODE>CONFIG_SITE</CODE> environment variable to the location of the site +script. A warning: the Bash <CODE>configure</CODE> looks for a site script, +but not all <CODE>configure</CODE> scripts do. +</P><P> + +<A NAME="Operation Controls"></A> +<HR SIZE="6"> +<A NAME="SEC133"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC132"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC134"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC134"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC126"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC135"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H2> 10.7 Operation Controls </H2> +<!--docid::SEC133::--> +<P> + +<CODE>configure</CODE> recognizes the following options to control how it +operates. +</P><P> + +<DL COMPACT> + +<DT><CODE>--cache-file=<VAR>file</VAR></CODE> +<DD>Use and save the results of the tests in +<VAR>file</VAR> instead of <TT>`./config.cache'</TT>. Set <VAR>file</VAR> to +<TT>`/dev/null'</TT> to disable caching, for debugging +<CODE>configure</CODE>. +<P> + +<DT><CODE>--help</CODE> +<DD>Print a summary of the options to <CODE>configure</CODE>, and exit. +<P> + +<DT><CODE>--quiet</CODE> +<DD><DT><CODE>--silent</CODE> +<DD><DT><CODE>-q</CODE> +<DD>Do not print messages saying which checks are being made. +<P> + +<DT><CODE>--srcdir=<VAR>dir</VAR></CODE> +<DD>Look for the Bash source code in directory <VAR>dir</VAR>. Usually +<CODE>configure</CODE> can determine that directory automatically. +<P> + +<DT><CODE>--version</CODE> +<DD>Print the version of Autoconf used to generate the <CODE>configure</CODE> +script, and exit. +</DL> +<P> + +<CODE>configure</CODE> also accepts some other, not widely used, boilerplate +options. <SAMP>`configure --help'</SAMP> prints the complete list. +</P><P> + +<A NAME="Optional Features"></A> +<HR SIZE="6"> +<A NAME="SEC134"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC133"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC135"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC126"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC126"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC135"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H2> 10.8 Optional Features </H2> +<!--docid::SEC134::--> +<P> + +The Bash <CODE>configure</CODE> has a number of <SAMP>`--enable-<VAR>feature</VAR>'</SAMP> +options, where <VAR>feature</VAR> indicates an optional part of Bash. +There are also several <SAMP>`--with-<VAR>package</VAR>'</SAMP> options, +where <VAR>package</VAR> is something like <SAMP>`bash-malloc'</SAMP> or <SAMP>`purify'</SAMP>. +To turn off the default use of a package, use +<SAMP>`--without-<VAR>package</VAR>'</SAMP>. To configure Bash without a feature +that is enabled by default, use <SAMP>`--disable-<VAR>feature</VAR>'</SAMP>. +</P><P> + +Here is a complete list of the <SAMP>`--enable-'</SAMP> and +<SAMP>`--with-'</SAMP> options that the Bash <CODE>configure</CODE> recognizes. +</P><P> + +<DL COMPACT> +<DT><CODE>--with-afs</CODE> +<DD>Define if you are using the Andrew File System from Transarc. +<P> + +<DT><CODE>--with-bash-malloc</CODE> +<DD>Use the Bash version of +<CODE>malloc</CODE> in the directory <TT>`lib/malloc'</TT>. This is not the same +<CODE>malloc</CODE> that appears in GNU libc, but an older version +originally derived from the 4.2 BSD <CODE>malloc</CODE>. This <CODE>malloc</CODE> +is very fast, but wastes some space on each allocation. +This option is enabled by default. +The <TT>`NOTES'</TT> file contains a list of systems for +which this should be turned off, and <CODE>configure</CODE> disables this +option automatically for a number of systems. +<P> + +<DT><CODE>--with-curses</CODE> +<DD>Use the curses library instead of the termcap library. This should +be supplied if your system has an inadequate or incomplete termcap +database. +<P> + +<DT><CODE>--with-gnu-malloc</CODE> +<DD>A synonym for <CODE>--with-bash-malloc</CODE>. +<P> + +<DT><CODE>--with-installed-readline[=<VAR>PREFIX</VAR>]</CODE> +<DD>Define this to make Bash link with a locally-installed version of Readline +rather than the version in <TT>`lib/readline'</TT>. This works only with +Readline 5.0 and later versions. If <VAR>PREFIX</VAR> is <CODE>yes</CODE> or not +supplied, <CODE>configure</CODE> uses the values of the make variables +<CODE>includedir</CODE> and <CODE>libdir</CODE>, which are subdirectories of <CODE>prefix</CODE> +by default, to find the installed version of Readline if it is not in +the standard system include and library directories. +If <VAR>PREFIX</VAR> is <CODE>no</CODE>, Bash links with the version in +<TT>`lib/readline'</TT>. +If <VAR>PREFIX</VAR> is set to any other value, <CODE>configure</CODE> treats it as +a directory pathname and looks for +the installed version of Readline in subdirectories of that directory +(include files in <VAR>PREFIX</VAR>/<CODE>include</CODE> and the library in +<VAR>PREFIX</VAR>/<CODE>lib</CODE>). +<P> + +<DT><CODE>--with-purify</CODE> +<DD>Define this to use the Purify memory allocation checker from Rational +Software. +<P> + +<DT><CODE>--enable-minimal-config</CODE> +<DD>This produces a shell with minimal features, close to the historical +Bourne shell. +</DL> +<P> + +There are several <SAMP>`--enable-'</SAMP> options that alter how Bash is +compiled and linked, rather than changing run-time features. +</P><P> + +<DL COMPACT> +<DT><CODE>--enable-largefile</CODE> +<DD>Enable support for <A HREF="http://www.sas.com/standards/large_file/x_open.20Mar96.html">large files</A> if the operating system requires special compiler options +to build programs which can access large files. This is enabled by +default, if the operating system provides large file support. +<P> + +<DT><CODE>--enable-profiling</CODE> +<DD>This builds a Bash binary that produces profiling information to be +processed by <CODE>gprof</CODE> each time it is executed. +<P> + +<DT><CODE>--enable-static-link</CODE> +<DD>This causes Bash to be linked statically, if <CODE>gcc</CODE> is being used. +This could be used to build a version to use as root's shell. +</DL> +<P> + +The <SAMP>`minimal-config'</SAMP> option can be used to disable all of +the following options, but it is processed first, so individual +options may be enabled using <SAMP>`enable-<VAR>feature</VAR>'</SAMP>. +</P><P> + +All of the following options except for <SAMP>`disabled-builtins'</SAMP> and +<SAMP>`xpg-echo-default'</SAMP> are +enabled by default, unless the operating system does not provide the +necessary support. +</P><P> + +<DL COMPACT> +<DT><CODE>--enable-alias</CODE> +<DD>Allow alias expansion and include the <CODE>alias</CODE> and <CODE>unalias</CODE> +builtins (see section <A HREF="bashref.html#SEC84">6.6 Aliases</A>). +<P> + +<DT><CODE>--enable-arith-for-command</CODE> +<DD>Include support for the alternate form of the <CODE>for</CODE> command +that behaves like the C language <CODE>for</CODE> statement +(see section <A HREF="bashref.html#SEC20">3.2.4.1 Looping Constructs</A>). +<P> + +<DT><CODE>--enable-array-variables</CODE> +<DD>Include support for one-dimensional array shell variables +(see section <A HREF="bashref.html#SEC85">6.7 Arrays</A>). +<P> + +<DT><CODE>--enable-bang-history</CODE> +<DD>Include support for <CODE>csh</CODE>-like history substitution +(see section <A HREF="bashref.html#SEC122">9.3 History Expansion</A>). +<P> + +<DT><CODE>--enable-brace-expansion</CODE> +<DD>Include <CODE>csh</CODE>-like brace expansion +( <CODE>b{a,b}c</CODE> ==> <CODE>bac bbc</CODE> ). +See <A HREF="bashref.html#SEC29">3.5.1 Brace Expansion</A>, for a complete description. +<P> + +<DT><CODE>--enable-casemod-attributes</CODE> +<DD>Include support for case-modifying attributes in the <CODE>declare</CODE> builtin +and assignment statements. Variables with the <VAR>uppercase</VAR> attribute, +for example, will have their values converted to uppercase upon assignment. +<P> + +<DT><CODE>--enable-casemod-expansion</CODE> +<DD>Include support for case-modifying word expansions. +<P> + +<DT><CODE>--enable-command-timing</CODE> +<DD>Include support for recognizing <CODE>time</CODE> as a reserved word and for +displaying timing statistics for the pipeline following <CODE>time</CODE> +(see section <A HREF="bashref.html#SEC17">3.2.2 Pipelines</A>). +This allows pipelines as well as shell builtins and functions to be timed. +<P> + +<DT><CODE>--enable-cond-command</CODE> +<DD>Include support for the <CODE>[[</CODE> conditional command. +(see section <A HREF="bashref.html#SEC21">3.2.4.2 Conditional Constructs</A>). +<P> + +<DT><CODE>--enable-cond-regexp</CODE> +<DD>Include support for matching POSIX regular expressions using the +<SAMP>`=~'</SAMP> binary operator in the <CODE>[[</CODE> conditional command. +(see section <A HREF="bashref.html#SEC21">3.2.4.2 Conditional Constructs</A>). +<P> + +<DT><CODE>--enable-coprocesses</CODE> +<DD>Include support for coprocesses and the <CODE>coproc</CODE> reserved word +(see section <A HREF="bashref.html#SEC17">3.2.2 Pipelines</A>). +<P> + +<DT><CODE>--enable-debugger</CODE> +<DD>Include support for the bash debugger (distributed separately). +<P> + +<DT><CODE>--enable-directory-stack</CODE> +<DD>Include support for a <CODE>csh</CODE>-like directory stack and the +<CODE>pushd</CODE>, <CODE>popd</CODE>, and <CODE>dirs</CODE> builtins +(see section <A HREF="bashref.html#SEC86">6.8 The Directory Stack</A>). +<P> + +<DT><CODE>--enable-disabled-builtins</CODE> +<DD>Allow builtin commands to be invoked via <SAMP>`builtin xxx'</SAMP> +even after <CODE>xxx</CODE> has been disabled using <SAMP>`enable -n xxx'</SAMP>. +See <A HREF="bashref.html#SEC60">4.2 Bash Builtin Commands</A>, for details of the <CODE>builtin</CODE> and +<CODE>enable</CODE> builtin commands. +<P> + +<DT><CODE>--enable-dparen-arithmetic</CODE> +<DD>Include support for the <CODE>((<small>...</small>))</CODE> command +(see section <A HREF="bashref.html#SEC21">3.2.4.2 Conditional Constructs</A>). +<P> + +<DT><CODE>--enable-extended-glob</CODE> +<DD>Include support for the extended pattern matching features described +above under <A HREF="bashref.html#SEC37">3.5.8.1 Pattern Matching</A>. +<P> + +<DT><CODE>--enable-extended-glob-default</CODE> +<DD>Set the default value of the <VAR>extglob</VAR> shell option described +above under <A HREF="bashref.html#SEC63">4.3.2 The Shopt Builtin</A> to be enabled. +<P> + +<DT><CODE>--enable-help-builtin</CODE> +<DD>Include the <CODE>help</CODE> builtin, which displays help on shell builtins and +variables (see section <A HREF="bashref.html#SEC60">4.2 Bash Builtin Commands</A>). +<P> + +<DT><CODE>--enable-history</CODE> +<DD>Include command history and the <CODE>fc</CODE> and <CODE>history</CODE> +builtin commands (see section <A HREF="bashref.html#SEC120">9.1 Bash History Facilities</A>). +<P> + +<DT><CODE>--enable-job-control</CODE> +<DD>This enables the job control features (see section <A HREF="bashref.html#SEC91">7. Job Control</A>), +if the operating system supports them. +<P> + +<DT><CODE>--enable-multibyte</CODE> +<DD>This enables support for multibyte characters if the operating +system provides the necessary support. +<P> + +<DT><CODE>--enable-net-redirections</CODE> +<DD>This enables the special handling of filenames of the form +<CODE>/dev/tcp/<VAR>host</VAR>/<VAR>port</VAR></CODE> and +<CODE>/dev/udp/<VAR>host</VAR>/<VAR>port</VAR></CODE> +when used in redirections (see section <A HREF="bashref.html#SEC39">3.6 Redirections</A>). +<P> + +<DT><CODE>--enable-process-substitution</CODE> +<DD>This enables process substitution (see section <A HREF="bashref.html#SEC34">3.5.6 Process Substitution</A>) if +the operating system provides the necessary support. +<P> + +<DT><CODE>--enable-progcomp</CODE> +<DD>Enable the programmable completion facilities +(see section <A HREF="bashref.html#SEC117">8.6 Programmable Completion</A>). +If Readline is not enabled, this option has no effect. +<P> + +<DT><CODE>--enable-prompt-string-decoding</CODE> +<DD>Turn on the interpretation of a number of backslash-escaped characters +in the <CODE>$PS1</CODE>, <CODE>$PS2</CODE>, <CODE>$PS3</CODE>, and <CODE>$PS4</CODE> prompt +strings. See <A HREF="bashref.html#SEC88">6.9 Controlling the Prompt</A>, for a complete list of prompt +string escape sequences. +<P> + +<DT><CODE>--enable-readline</CODE> +<DD>Include support for command-line editing and history with the Bash +version of the Readline library (see section <A HREF="bashref.html#SEC95">8. Command Line Editing</A>). +<P> + +<DT><CODE>--enable-restricted</CODE> +<DD>Include support for a <EM>restricted shell</EM>. If this is enabled, Bash, +when called as <CODE>rbash</CODE>, enters a restricted mode. See +<A HREF="bashref.html#SEC89">6.10 The Restricted Shell</A>, for a description of restricted mode. +<P> + +<DT><CODE>--enable-select</CODE> +<DD>Include the <CODE>select</CODE> builtin, which allows the generation of simple +menus (see section <A HREF="bashref.html#SEC21">3.2.4.2 Conditional Constructs</A>). +<P> + +<DT><CODE>--enable-separate-helpfiles</CODE> +<DD>Use external files for the documentation displayed by the <CODE>help</CODE> builtin +instead of storing the text internally. +<P> + +<DT><CODE>--enable-single-help-strings</CODE> +<DD>Store the text displayed by the <CODE>help</CODE> builtin as a single string for +each help topic. This aids in translating the text to different languages. +You may need to disable this if your compiler cannot handle very long string +literals. +<P> + +<DT><CODE>--enable-strict-posix-default</CODE> +<DD>Make Bash POSIX-conformant by default (see section <A HREF="bashref.html#SEC90">6.11 Bash POSIX Mode</A>). +<P> + +<DT><CODE>--enable-usg-echo-default</CODE> +<DD>A synonym for <CODE>--enable-xpg-echo-default</CODE>. +<P> + +<DT><CODE>--enable-xpg-echo-default</CODE> +<DD>Make the <CODE>echo</CODE> builtin expand backslash-escaped characters by default, +without requiring the <SAMP>`-e'</SAMP> option. +This sets the default value of the <CODE>xpg_echo</CODE> shell option to <CODE>on</CODE>, +which makes the Bash <CODE>echo</CODE> behave more like the version specified in +the Single Unix Specification, version 3. +See section <A HREF="bashref.html#SEC60">4.2 Bash Builtin Commands</A>, for a description of the escape sequences that +<CODE>echo</CODE> recognizes. +<P> + +</DL> +<P> + +The file <TT>`config-top.h'</TT> contains C Preprocessor +<SAMP>`#define'</SAMP> statements for options which are not settable from +<CODE>configure</CODE>. +Some of these are not meant to be changed; beware of the consequences if +you do. +Read the comments associated with each definition for more +information about its effect. +</P><P> + +<A NAME="Reporting Bugs"></A> +<HR SIZE="6"> +<A NAME="SEC135"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC134"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC136"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC126"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC136"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H1> A. Reporting Bugs </H1> +<!--docid::SEC135::--> +<P> + +Please report all bugs you find in Bash. +But first, you should +make sure that it really is a bug, and that it appears in the latest +version of Bash. +The latest version of Bash is always available for FTP from +<A HREF="ftp://ftp.gnu.org/pub/gnu/bash/">ftp://ftp.gnu.org/pub/gnu/bash/</A>. +</P><P> + +Once you have determined that a bug actually exists, use the +<CODE>bashbug</CODE> command to submit a bug report. +If you have a fix, you are encouraged to mail that as well! +Suggestions and `philosophical' bug reports may be mailed +to <A HREF="mailto:bug-bash@gnu.org">bug-bash@gnu.org</A> or posted to the Usenet +newsgroup <CODE>gnu.bash.bug</CODE>. +</P><P> + +All bug reports should include: +<UL> +<LI> +The version number of Bash. +<LI> +The hardware and operating system. +<LI> +The compiler used to compile Bash. +<LI> +A description of the bug behaviour. +<LI> +A short script or `recipe' which exercises the bug and may be used +to reproduce it. +</UL> +<P> + +<CODE>bashbug</CODE> inserts the first three items automatically into +the template it provides for filing a bug report. +</P><P> + +Please send all reports concerning this manual to +<A HREF="mailto:chet.ramey@case.edu">chet.ramey@case.edu</A>. +</P><P> + +<A NAME="Major Differences From The Bourne Shell"></A> +<HR SIZE="6"> +<A NAME="SEC136"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC135"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC137"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC138"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC138"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H1> B. Major Differences From The Bourne Shell </H1> +<!--docid::SEC136::--> +<P> + +Bash implements essentially the same grammar, parameter and +variable expansion, redirection, and quoting as the Bourne Shell. +Bash uses the POSIX standard as the specification of +how these features are to be implemented. There are some +differences between the traditional Bourne shell and Bash; this +section quickly details the differences of significance. A +number of these differences are explained in greater depth in +previous sections. +This section uses the version of <CODE>sh</CODE> included in SVR4.2 (the +last version of the historical Bourne shell) as the baseline reference. +</P><P> + +<UL> + +<LI> +Bash is POSIX-conformant, even where the POSIX specification +differs from traditional <CODE>sh</CODE> behavior (see section <A HREF="bashref.html#SEC90">6.11 Bash POSIX Mode</A>). +<P> + +<LI> +Bash has multi-character invocation options (see section <A HREF="bashref.html#SEC69">6.1 Invoking Bash</A>). +<P> + +<LI> +Bash has command-line editing (see section <A HREF="bashref.html#SEC95">8. Command Line Editing</A>) and +the <CODE>bind</CODE> builtin. +<P> + +<LI> +Bash provides a programmable word completion mechanism +(see section <A HREF="bashref.html#SEC117">8.6 Programmable Completion</A>), and builtin commands +<CODE>complete</CODE>, <CODE>compgen</CODE>, and <CODE>compopt</CODE>, to +manipulate it. +<P> + +<LI> +Bash has command history (see section <A HREF="bashref.html#SEC120">9.1 Bash History Facilities</A>) and the +<CODE>history</CODE> and <CODE>fc</CODE> builtins to manipulate it. +The Bash history list maintains timestamp information and uses the +value of the <CODE>HISTTIMEFORMAT</CODE> variable to display it. +<P> + +<LI> +Bash implements <CODE>csh</CODE>-like history expansion +(see section <A HREF="bashref.html#SEC122">9.3 History Expansion</A>). +<P> + +<LI> +Bash has one-dimensional array variables (see section <A HREF="bashref.html#SEC85">6.7 Arrays</A>), and the +appropriate variable expansions and assignment syntax to use them. +Several of the Bash builtins take options to act on arrays. +Bash provides a number of built-in array variables. +<P> + +<LI> +The <CODE>$'<small>...</small>'</CODE> quoting syntax, which expands ANSI-C +backslash-escaped characters in the text between the single quotes, +is supported (see section <A HREF="bashref.html#SEC12">3.1.2.4 ANSI-C Quoting</A>). +<P> + +<LI> +Bash supports the <CODE>$"<small>...</small>"</CODE> quoting syntax to do +locale-specific translation of the characters between the double +quotes. The <SAMP>`-D'</SAMP>, <SAMP>`--dump-strings'</SAMP>, and <SAMP>`--dump-po-strings'</SAMP> +invocation options list the translatable strings found in a script +(see section <A HREF="bashref.html#SEC13">3.1.2.5 Locale-Specific Translation</A>). +<P> + +<LI> +Bash implements the <CODE>!</CODE> keyword to negate the return value of +a pipeline (see section <A HREF="bashref.html#SEC17">3.2.2 Pipelines</A>). +Very useful when an <CODE>if</CODE> statement needs to act only if a test fails. +The Bash <SAMP>`-o pipefail'</SAMP> option to <CODE>set</CODE> will cause a pipeline to +return a failure status if any command fails. +<P> + +<LI> +Bash has the <CODE>time</CODE> reserved word and command timing (see section <A HREF="bashref.html#SEC17">3.2.2 Pipelines</A>). +The display of the timing statistics may be controlled with the +<CODE>TIMEFORMAT</CODE> variable. +<P> + +<LI> +Bash implements the <CODE>for (( <VAR>expr1</VAR> ; <VAR>expr2</VAR> ; <VAR>expr3</VAR> ))</CODE> +arithmetic for command, similar to the C language (see section <A HREF="bashref.html#SEC20">3.2.4.1 Looping Constructs</A>). +<P> + +<LI> +Bash includes the <CODE>select</CODE> compound command, which allows the +generation of simple menus (see section <A HREF="bashref.html#SEC21">3.2.4.2 Conditional Constructs</A>). +<P> + +<LI> +Bash includes the <CODE>[[</CODE> compound command, which makes conditional +testing part of the shell grammar (see section <A HREF="bashref.html#SEC21">3.2.4.2 Conditional Constructs</A>), including +optional regular expression matching. +<P> + +<LI> +Bash provides optional case-insensitive matching for the <CODE>case</CODE> and +<CODE>[[</CODE> constructs. +<P> + +<LI> +Bash includes brace expansion (see section <A HREF="bashref.html#SEC29">3.5.1 Brace Expansion</A>) and tilde +expansion (see section <A HREF="bashref.html#SEC30">3.5.2 Tilde Expansion</A>). +<P> + +<LI> +Bash implements command aliases and the <CODE>alias</CODE> and <CODE>unalias</CODE> +builtins (see section <A HREF="bashref.html#SEC84">6.6 Aliases</A>). +<P> + +<LI> +Bash provides shell arithmetic, the <CODE>((</CODE> compound command +(see section <A HREF="bashref.html#SEC21">3.2.4.2 Conditional Constructs</A>), +and arithmetic expansion (see section <A HREF="bashref.html#SEC83">6.5 Shell Arithmetic</A>). +<P> + +<LI> +Variables present in the shell's initial environment are automatically +exported to child processes. The Bourne shell does not normally do +this unless the variables are explicitly marked using the <CODE>export</CODE> +command. +<P> + +<LI> +Bash supports the <SAMP>`+='</SAMP> assignment operator, which appends to the value +of the variable named on the left hand side. +<P> + +<LI> +Bash includes the POSIX pattern removal <SAMP>`%'</SAMP>, <SAMP>`#'</SAMP>, <SAMP>`%%'</SAMP> +and <SAMP>`##'</SAMP> expansions to remove leading or trailing substrings from +variable values (see section <A HREF="bashref.html#SEC31">3.5.3 Shell Parameter Expansion</A>). +<P> + +<LI> +The expansion <CODE>${#xx}</CODE>, which returns the length of <CODE>${xx}</CODE>, +is supported (see section <A HREF="bashref.html#SEC31">3.5.3 Shell Parameter Expansion</A>). +<P> + +<LI> +The expansion <CODE>${var:</CODE><VAR>offset</VAR><CODE>[:</CODE><VAR>length</VAR><CODE>]}</CODE>, +which expands to the substring of <CODE>var</CODE>'s value of length +<VAR>length</VAR>, beginning at <VAR>offset</VAR>, is present +(see section <A HREF="bashref.html#SEC31">3.5.3 Shell Parameter Expansion</A>). +<P> + +<LI> +The expansion +<CODE>${var/[/]</CODE><VAR>pattern</VAR><CODE>[/</CODE><VAR>replacement</VAR><CODE>]}</CODE>, +which matches <VAR>pattern</VAR> and replaces it with <VAR>replacement</VAR> in +the value of <CODE>var</CODE>, is available (see section <A HREF="bashref.html#SEC31">3.5.3 Shell Parameter Expansion</A>). +<P> + +<LI> +The expansion <CODE>${!<VAR>prefix}*</VAR></CODE> expansion, which expands to +the names of all shell variables whose names begin with <VAR>prefix</VAR>, +is available (see section <A HREF="bashref.html#SEC31">3.5.3 Shell Parameter Expansion</A>). +<P> + +<LI> +Bash has <VAR>indirect</VAR> variable expansion using <CODE>${!word}</CODE> +(see section <A HREF="bashref.html#SEC31">3.5.3 Shell Parameter Expansion</A>). +<P> + +<LI> +Bash can expand positional parameters beyond <CODE>$9</CODE> using +<CODE>${<VAR>num</VAR>}</CODE>. +<P> + +<LI> +The POSIX <CODE>$()</CODE> form of command substitution +is implemented (see section <A HREF="bashref.html#SEC32">3.5.4 Command Substitution</A>), +and preferred to the Bourne shell's <CODE>"</CODE> (which +is also implemented for backwards compatibility). +<P> + +<LI> +Bash has process substitution (see section <A HREF="bashref.html#SEC34">3.5.6 Process Substitution</A>). +<P> + +<LI> +Bash automatically assigns variables that provide information about the +current user (<CODE>UID</CODE>, <CODE>EUID</CODE>, and <CODE>GROUPS</CODE>), the current host +(<CODE>HOSTTYPE</CODE>, <CODE>OSTYPE</CODE>, <CODE>MACHTYPE</CODE>, and <CODE>HOSTNAME</CODE>), +and the instance of Bash that is running (<CODE>BASH</CODE>, +<CODE>BASH_VERSION</CODE>, and <CODE>BASH_VERSINFO</CODE>). See section <A HREF="bashref.html#SEC67">5.2 Bash Variables</A>, +for details. +<P> + +<LI> +The <CODE>IFS</CODE> variable is used to split only the results of expansion, +not all words (see section <A HREF="bashref.html#SEC35">3.5.7 Word Splitting</A>). +This closes a longstanding shell security hole. +<P> + +<LI> +Bash implements the full set of POSIX filename expansion operators, +including <VAR>character classes</VAR>, <VAR>equivalence classes</VAR>, and +<VAR>collating symbols</VAR> (see section <A HREF="bashref.html#SEC36">3.5.8 Filename Expansion</A>). +<P> + +<LI> +Bash implements extended pattern matching features when the <CODE>extglob</CODE> +shell option is enabled (see section <A HREF="bashref.html#SEC37">3.5.8.1 Pattern Matching</A>). +<P> + +<LI> +It is possible to have a variable and a function with the same name; +<CODE>sh</CODE> does not separate the two name spaces. +<P> + +<LI> +Bash functions are permitted to have local variables using the +<CODE>local</CODE> builtin, and thus useful recursive functions may be written +(see section <A HREF="bashref.html#SEC60">4.2 Bash Builtin Commands</A>). +<P> + +<LI> +Variable assignments preceding commands affect only that command, even +builtins and functions (see section <A HREF="bashref.html#SEC54">3.7.4 Environment</A>). +In <CODE>sh</CODE>, all variable assignments +preceding commands are global unless the command is executed from the +file system. +<P> + +<LI> +Bash performs filename expansion on filenames specified as operands +to input and output redirection operators (see section <A HREF="bashref.html#SEC39">3.6 Redirections</A>). +<P> + +<LI> +Bash contains the <SAMP>`<>'</SAMP> redirection operator, allowing a file to be +opened for both reading and writing, and the <SAMP>`&>'</SAMP> redirection +operator, for directing standard output and standard error to the same +file (see section <A HREF="bashref.html#SEC39">3.6 Redirections</A>). +<P> + +<LI> +Bash includes the <SAMP>`<<<'</SAMP> redirection operator, allowing a string to +be used as the standard input to a command. +<P> + +<LI> +Bash implements the <SAMP>`[n]<&<VAR>word</VAR>'</SAMP> and <SAMP>`[n]>&<VAR>word</VAR>'</SAMP> +redirection operators, which move one file descriptor to another. +<P> + +<LI> +Bash treats a number of filenames specially when they are +used in redirection operators (see section <A HREF="bashref.html#SEC39">3.6 Redirections</A>). +<P> + +<LI> +Bash can open network connections to arbitrary machines and services +with the redirection operators (see section <A HREF="bashref.html#SEC39">3.6 Redirections</A>). +<P> + +<LI> +The <CODE>noclobber</CODE> option is available to avoid overwriting existing +files with output redirection (see section <A HREF="bashref.html#SEC62">4.3.1 The Set Builtin</A>). +The <SAMP>`>|'</SAMP> redirection operator may be used to override <CODE>noclobber</CODE>. +<P> + +<LI> +The Bash <CODE>cd</CODE> and <CODE>pwd</CODE> builtins (see section <A HREF="bashref.html#SEC59">4.1 Bourne Shell Builtins</A>) +each take <SAMP>`-L'</SAMP> and <SAMP>`-P'</SAMP> options to switch between logical and +physical modes. +<P> + +<LI> +Bash allows a function to override a builtin with the same name, and provides +access to that builtin's functionality within the function via the +<CODE>builtin</CODE> and <CODE>command</CODE> builtins (see section <A HREF="bashref.html#SEC60">4.2 Bash Builtin Commands</A>). +<P> + +<LI> +The <CODE>command</CODE> builtin allows selective disabling of functions +when command lookup is performed (see section <A HREF="bashref.html#SEC60">4.2 Bash Builtin Commands</A>). +<P> + +<LI> +Individual builtins may be enabled or disabled using the <CODE>enable</CODE> +builtin (see section <A HREF="bashref.html#SEC60">4.2 Bash Builtin Commands</A>). +<P> + +<LI> +The Bash <CODE>exec</CODE> builtin takes additional options that allow users +to control the contents of the environment passed to the executed +command, and what the zeroth argument to the command is to be +(see section <A HREF="bashref.html#SEC59">4.1 Bourne Shell Builtins</A>). +<P> + +<LI> +Shell functions may be exported to children via the environment +using <CODE>export -f</CODE> (see section <A HREF="bashref.html#SEC24">3.3 Shell Functions</A>). +<P> + +<LI> +The Bash <CODE>export</CODE>, <CODE>readonly</CODE>, and <CODE>declare</CODE> builtins can +take a <SAMP>`-f'</SAMP> option to act on shell functions, a <SAMP>`-p'</SAMP> option to +display variables with various attributes set in a format that can be +used as shell input, a <SAMP>`-n'</SAMP> option to remove various variable +attributes, and <SAMP>`name=value'</SAMP> arguments to set variable attributes +and values simultaneously. +<P> + +<LI> +The Bash <CODE>hash</CODE> builtin allows a name to be associated with +an arbitrary filename, even when that filename cannot be found by +searching the <CODE>$PATH</CODE>, using <SAMP>`hash -p'</SAMP> +(see section <A HREF="bashref.html#SEC59">4.1 Bourne Shell Builtins</A>). +<P> + +<LI> +Bash includes a <CODE>help</CODE> builtin for quick reference to shell +facilities (see section <A HREF="bashref.html#SEC60">4.2 Bash Builtin Commands</A>). +<P> + +<LI> +The <CODE>printf</CODE> builtin is available to display formatted output +(see section <A HREF="bashref.html#SEC60">4.2 Bash Builtin Commands</A>). +<P> + +<LI> +The Bash <CODE>read</CODE> builtin (see section <A HREF="bashref.html#SEC60">4.2 Bash Builtin Commands</A>) +will read a line ending in <SAMP>`\'</SAMP> with +the <SAMP>`-r'</SAMP> option, and will use the <CODE>REPLY</CODE> variable as a +default if no non-option arguments are supplied. +The Bash <CODE>read</CODE> builtin +also accepts a prompt string with the <SAMP>`-p'</SAMP> option and will use +Readline to obtain the line when given the <SAMP>`-e'</SAMP> option. +The <CODE>read</CODE> builtin also has additional options to control input: +the <SAMP>`-s'</SAMP> option will turn off echoing of input characters as +they are read, the <SAMP>`-t'</SAMP> option will allow <CODE>read</CODE> to time out +if input does not arrive within a specified number of seconds, the +<SAMP>`-n'</SAMP> option will allow reading only a specified number of +characters rather than a full line, and the <SAMP>`-d'</SAMP> option will read +until a particular character rather than newline. +<P> + +<LI> +The <CODE>return</CODE> builtin may be used to abort execution of scripts +executed with the <CODE>.</CODE> or <CODE>source</CODE> builtins +(see section <A HREF="bashref.html#SEC59">4.1 Bourne Shell Builtins</A>). +<P> + +<LI> +Bash includes the <CODE>shopt</CODE> builtin, for finer control of shell +optional capabilities (see section <A HREF="bashref.html#SEC63">4.3.2 The Shopt Builtin</A>), and allows these options +to be set and unset at shell invocation (see section <A HREF="bashref.html#SEC69">6.1 Invoking Bash</A>). +<P> + +<LI> +Bash has much more optional behavior controllable with the <CODE>set</CODE> +builtin (see section <A HREF="bashref.html#SEC62">4.3.1 The Set Builtin</A>). +<P> + +<LI> +The <SAMP>`-x'</SAMP> (<CODE>xtrace</CODE>) option displays commands other than +simple commands when performing an execution trace +(see section <A HREF="bashref.html#SEC62">4.3.1 The Set Builtin</A>). +<P> + +<LI> +The <CODE>test</CODE> builtin (see section <A HREF="bashref.html#SEC59">4.1 Bourne Shell Builtins</A>) +is slightly different, as it implements the POSIX algorithm, +which specifies the behavior based on the number of arguments. +<P> + +<LI> +Bash includes the <CODE>caller</CODE> builtin, which displays the context of +any active subroutine call (a shell function or a script executed with +the <CODE>.</CODE> or <CODE>source</CODE> builtins). This supports the bash +debugger. +<P> + +<LI> +The <CODE>trap</CODE> builtin (see section <A HREF="bashref.html#SEC59">4.1 Bourne Shell Builtins</A>) allows a +<CODE>DEBUG</CODE> pseudo-signal specification, similar to <CODE>EXIT</CODE>. +Commands specified with a <CODE>DEBUG</CODE> trap are executed before every +simple command, <CODE>for</CODE> command, <CODE>case</CODE> command, +<CODE>select</CODE> command, every arithmetic <CODE>for</CODE> command, and before +the first command executes in a shell function. +The <CODE>DEBUG</CODE> trap is not inherited by shell functions unless the +function has been given the <CODE>trace</CODE> attribute or the +<CODE>functrace</CODE> option has been enabled using the <CODE>shopt</CODE> builtin. +The <CODE>extdebug</CODE> shell option has additional effects on the +<CODE>DEBUG</CODE> trap. +<P> + +The <CODE>trap</CODE> builtin (see section <A HREF="bashref.html#SEC59">4.1 Bourne Shell Builtins</A>) allows an +<CODE>ERR</CODE> pseudo-signal specification, similar to <CODE>EXIT</CODE> and <CODE>DEBUG</CODE>. +Commands specified with an <CODE>ERR</CODE> trap are executed after a simple +command fails, with a few exceptions. +The <CODE>ERR</CODE> trap is not inherited by shell functions unless the +<CODE>-o errtrace</CODE> option to the <CODE>set</CODE> builtin is enabled. +</P><P> + +The <CODE>trap</CODE> builtin (see section <A HREF="bashref.html#SEC59">4.1 Bourne Shell Builtins</A>) allows a +<CODE>RETURN</CODE> pseudo-signal specification, similar to +<CODE>EXIT</CODE> and <CODE>DEBUG</CODE>. +Commands specified with an <CODE>RETURN</CODE> trap are executed before +execution resumes after a shell function or a shell script executed with +<CODE>.</CODE> or <CODE>source</CODE> returns. +The <CODE>RETURN</CODE> trap is not inherited by shell functions unless the +function has been given the <CODE>trace</CODE> attribute or the +<CODE>functrace</CODE> option has been enabled using the <CODE>shopt</CODE> builtin. +</P><P> + +<LI> +The Bash <CODE>type</CODE> builtin is more extensive and gives more information +about the names it finds (see section <A HREF="bashref.html#SEC60">4.2 Bash Builtin Commands</A>). +<P> + +<LI> +The Bash <CODE>umask</CODE> builtin permits a <SAMP>`-p'</SAMP> option to cause +the output to be displayed in the form of a <CODE>umask</CODE> command +that may be reused as input (see section <A HREF="bashref.html#SEC59">4.1 Bourne Shell Builtins</A>). +<P> + +<LI> +Bash implements a <CODE>csh</CODE>-like directory stack, and provides the +<CODE>pushd</CODE>, <CODE>popd</CODE>, and <CODE>dirs</CODE> builtins to manipulate it +(see section <A HREF="bashref.html#SEC86">6.8 The Directory Stack</A>). +Bash also makes the directory stack visible as the value of the +<CODE>DIRSTACK</CODE> shell variable. +<P> + +<LI> +Bash interprets special backslash-escaped characters in the prompt +strings when interactive (see section <A HREF="bashref.html#SEC88">6.9 Controlling the Prompt</A>). +<P> + +<LI> +The Bash restricted mode is more useful (see section <A HREF="bashref.html#SEC89">6.10 The Restricted Shell</A>); +the SVR4.2 shell restricted mode is too limited. +<P> + +<LI> +The <CODE>disown</CODE> builtin can remove a job from the internal shell +job table (see section <A HREF="bashref.html#SEC93">7.2 Job Control Builtins</A>) or suppress the sending +of <CODE>SIGHUP</CODE> to a job when the shell exits as the result of a +<CODE>SIGHUP</CODE>. +<P> + +<LI> +Bash includes a number of features to support a separate debugger for +shell scripts. +<P> + +<LI> +The SVR4.2 shell has two privilege-related builtins +(<CODE>mldmode</CODE> and <CODE>priv</CODE>) not present in Bash. +<P> + +<LI> +Bash does not have the <CODE>stop</CODE> or <CODE>newgrp</CODE> builtins. +<P> + +<LI> +Bash does not use the <CODE>SHACCT</CODE> variable or perform shell accounting. +<P> + +<LI> +The SVR4.2 <CODE>sh</CODE> uses a <CODE>TIMEOUT</CODE> variable like Bash uses +<CODE>TMOUT</CODE>. +<P> + +</UL> +<P> + +More features unique to Bash may be found in <A HREF="bashref.html#SEC68">6. Bash Features</A>. +</P><P> + +<HR SIZE="6"> +<A NAME="SEC137"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC136"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC138"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC136"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC136"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC138"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H2> B.1 Implementation Differences From The SVR4.2 Shell </H2> +<!--docid::SEC137::--> +<P> + +Since Bash is a completely new implementation, it does not suffer from +many of the limitations of the SVR4.2 shell. For instance: +</P><P> + +<UL> + +<LI> +Bash does not fork a subshell when redirecting into or out of +a shell control structure such as an <CODE>if</CODE> or <CODE>while</CODE> +statement. +<P> + +<LI> +Bash does not allow unbalanced quotes. The SVR4.2 shell will silently +insert a needed closing quote at <CODE>EOF</CODE> under certain circumstances. +This can be the cause of some hard-to-find errors. +<P> + +<LI> +The SVR4.2 shell uses a baroque memory management scheme based on +trapping <CODE>SIGSEGV</CODE>. If the shell is started from a process with +<CODE>SIGSEGV</CODE> blocked (e.g., by using the <CODE>system()</CODE> C library +function call), it misbehaves badly. +<P> + +<LI> +In a questionable attempt at security, the SVR4.2 shell, +when invoked without the <SAMP>`-p'</SAMP> option, will alter its real +and effective UID and GID if they are less than some +magic threshold value, commonly 100. +This can lead to unexpected results. +<P> + +<LI> +The SVR4.2 shell does not allow users to trap <CODE>SIGSEGV</CODE>, +<CODE>SIGALRM</CODE>, or <CODE>SIGCHLD</CODE>. +<P> + +<LI> +The SVR4.2 shell does not allow the <CODE>IFS</CODE>, <CODE>MAILCHECK</CODE>, +<CODE>PATH</CODE>, <CODE>PS1</CODE>, or <CODE>PS2</CODE> variables to be unset. +<P> + +<LI> +The SVR4.2 shell treats <SAMP>`^'</SAMP> as the undocumented equivalent of +<SAMP>`|'</SAMP>. +<P> + +<LI> +Bash allows multiple option arguments when it is invoked (<CODE>-x -v</CODE>); +the SVR4.2 shell allows only one option argument (<CODE>-xv</CODE>). In +fact, some versions of the shell dump core if the second argument begins +with a <SAMP>`-'</SAMP>. +<P> + +<LI> +The SVR4.2 shell exits a script if any builtin fails; Bash exits +a script only if one of the POSIX special builtins fails, and +only for certain failures, as enumerated in the POSIX standard. +<P> + +<LI> +The SVR4.2 shell behaves differently when invoked as <CODE>jsh</CODE> +(it turns on job control). +</UL> +<P> + +<A NAME="GNU Free Documentation License"></A> +<HR SIZE="6"> +<A NAME="SEC138"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC137"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140"> >> </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H1> C. GNU Free Documentation License </H1> +<!--docid::SEC138::--> +<P> + +<center> + Version 1.3, 3 November 2008 +</center> +</P><P> + +<TABLE><tr><td> </td><td class=display><pre style="font-family: serif">Copyright (C) 2000, 2001, 2002, 2007, 2008 Free Software Foundation, Inc. +<A HREF="http://fsf.org/">http://fsf.org/</A> + +Everyone is permitted to copy and distribute verbatim copies +of this license document, but changing it is not allowed. +</pre></td></tr></table></P><P> + +<OL> +<LI> +PREAMBLE +<P> + +The purpose of this License is to make a manual, textbook, or other +functional and useful document <EM>free</EM> in the sense of freedom: to +assure everyone the effective freedom to copy and redistribute it, +with or without modifying it, either commercially or noncommercially. +Secondarily, this License preserves for the author and publisher a way +to get credit for their work, while not being considered responsible +for modifications made by others. +</P><P> + +This License is a kind of "copyleft", which means that derivative +works of the document must themselves be free in the same sense. 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A copy of the license is included in the section entitled ``GNU + Free Documentation License''. +</FONT></pre></td></tr></table></P><P> + +If you have Invariant Sections, Front-Cover Texts and Back-Cover Texts, +replace the "with<small>...</small>Texts." line with this: +</P><P> + +<TABLE><tr><td> </td><td class=smallexample><FONT SIZE=-1><pre> with the Invariant Sections being <VAR>list their titles</VAR>, with + the Front-Cover Texts being <VAR>list</VAR>, and with the Back-Cover Texts + being <VAR>list</VAR>. +</FONT></pre></td></tr></table></P><P> + +If you have Invariant Sections without Cover Texts, or some other +combination of the three, merge those two alternatives to suit the +situation. +</P><P> + +If your document contains nontrivial examples of program code, we +recommend releasing these examples in parallel under your choice of +free software license, such as the GNU General Public License, +to permit their use in free software. +</P><P> + +<A NAME="Indexes"></A> +<HR SIZE="6"> +<A NAME="SEC140"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC138"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC141"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[ << ]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[ >> ]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H1> D. Indexes </H1> +<!--docid::SEC140::--> +<P> + +<BLOCKQUOTE><TABLE BORDER=0 CELLSPACING=0> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC141">D.1 Index of Shell Builtin Commands</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Index of Bash builtin commands.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC142">D.2 Index of Shell Reserved Words</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Index of Bash reserved words.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC143">D.3 Parameter and Variable Index</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Quick reference helps you find the + variable you want.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC144">D.4 Function Index</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Index of bindable Readline functions.</TD></TR> +<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="bashref.html#SEC145">D.5 Concept Index</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">General index for concepts described in + this manual.</TD></TR> +</TABLE></BLOCKQUOTE> +<P> + +<A NAME="Builtin Index"></A> +<HR SIZE="6"> +<A NAME="SEC141"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC142"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[ << ]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[ >> ]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H2> D.1 Index of Shell Builtin Commands </H2> +<!--docid::SEC141::--> +<table><tr><th valign=top>Jump to: </th><td><A HREF="bashref.html#bt_." style="text-decoration:none"><b>.</b></A> + +<A HREF="bashref.html#bt_:" style="text-decoration:none"><b>:</b></A> + +<A HREF="bashref.html#bt_[" style="text-decoration:none"><b>[</b></A> + +<BR> +<A HREF="bashref.html#bt_A" style="text-decoration:none"><b>A</b></A> + +<A HREF="bashref.html#bt_B" style="text-decoration:none"><b>B</b></A> + +<A HREF="bashref.html#bt_C" style="text-decoration:none"><b>C</b></A> + +<A HREF="bashref.html#bt_D" style="text-decoration:none"><b>D</b></A> + +<A HREF="bashref.html#bt_E" style="text-decoration:none"><b>E</b></A> + +<A HREF="bashref.html#bt_F" style="text-decoration:none"><b>F</b></A> + +<A HREF="bashref.html#bt_G" style="text-decoration:none"><b>G</b></A> + +<A HREF="bashref.html#bt_H" style="text-decoration:none"><b>H</b></A> + +<A HREF="bashref.html#bt_J" style="text-decoration:none"><b>J</b></A> + +<A HREF="bashref.html#bt_K" style="text-decoration:none"><b>K</b></A> + +<A HREF="bashref.html#bt_L" style="text-decoration:none"><b>L</b></A> + +<A HREF="bashref.html#bt_M" style="text-decoration:none"><b>M</b></A> + +<A HREF="bashref.html#bt_P" style="text-decoration:none"><b>P</b></A> + +<A HREF="bashref.html#bt_R" style="text-decoration:none"><b>R</b></A> + +<A HREF="bashref.html#bt_S" style="text-decoration:none"><b>S</b></A> + +<A HREF="bashref.html#bt_T" style="text-decoration:none"><b>T</b></A> + +<A HREF="bashref.html#bt_U" style="text-decoration:none"><b>U</b></A> + +<A HREF="bashref.html#bt_W" style="text-decoration:none"><b>W</b></A> + +</td></tr></table><br><P></P> +<TABLE border=0> +<TR><TD></TD><TH ALIGN=LEFT>Index Entry</TH><TH ALIGN=LEFT> Section</TH></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="bt_."></A>.</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX69"><CODE>.</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC59">4.1 Bourne Shell Builtins</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="bt_:"></A>:</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX68"><CODE>:</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC59">4.1 Bourne Shell Builtins</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="bt_["></A>[</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX84"><CODE>[</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC59">4.1 Bourne Shell Builtins</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="bt_A"></A>A</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX89"><CODE>alias</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC60">4.2 Bash Builtin Commands</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="bt_B"></A>B</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX293"><CODE>bg</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC93">7.2 Job Control Builtins</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX90"><CODE>bind</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC60">4.2 Bash Builtin Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX70"><CODE>break</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC59">4.1 Bourne Shell Builtins</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX91"><CODE>builtin</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC60">4.2 Bash Builtin Commands</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="bt_C"></A>C</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX92"><CODE>caller</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC60">4.2 Bash Builtin Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX71"><CODE>cd</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC59">4.1 Bourne Shell Builtins</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX93"><CODE>command</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC60">4.2 Bash Builtin Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX540"><CODE>compgen</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC118">8.7 Programmable Completion Builtins</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX541"><CODE>complete</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC118">8.7 Programmable Completion Builtins</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX542"><CODE>compopt</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC118">8.7 Programmable Completion Builtins</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX72"><CODE>continue</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC59">4.1 Bourne Shell Builtins</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="bt_D"></A>D</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX94"><CODE>declare</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC60">4.2 Bash Builtin Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX290"><CODE>dirs</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC87">6.8.1 Directory Stack Builtins</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX298"><CODE>disown</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC93">7.2 Job Control Builtins</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="bt_E"></A>E</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX95"><CODE>echo</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC60">4.2 Bash Builtin Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX96"><CODE>enable</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC60">4.2 Bash Builtin Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX73"><CODE>eval</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC59">4.1 Bourne Shell Builtins</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX74"><CODE>exec</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC59">4.1 Bourne Shell Builtins</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX75"><CODE>exit</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC59">4.1 Bourne Shell Builtins</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX76"><CODE>export</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC59">4.1 Bourne Shell Builtins</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="bt_F"></A>F</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX544"><CODE>fc</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC121">9.2 Bash History Builtins</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX294"><CODE>fg</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC93">7.2 Job Control Builtins</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="bt_G"></A>G</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX77"><CODE>getopts</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC59">4.1 Bourne Shell Builtins</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="bt_H"></A>H</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX78"><CODE>hash</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC59">4.1 Bourne Shell Builtins</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX97"><CODE>help</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC60">4.2 Bash Builtin Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX545"><CODE>history</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC121">9.2 Bash History Builtins</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="bt_J"></A>J</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX295"><CODE>jobs</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC93">7.2 Job Control Builtins</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="bt_K"></A>K</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX296"><CODE>kill</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC93">7.2 Job Control Builtins</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="bt_L"></A>L</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX98"><CODE>let</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC60">4.2 Bash Builtin Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX99"><CODE>local</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC60">4.2 Bash Builtin Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX100"><CODE>logout</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC60">4.2 Bash Builtin Commands</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="bt_M"></A>M</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX101"><CODE>mapfile</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC60">4.2 Bash Builtin Commands</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="bt_P"></A>P</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX291"><CODE>popd</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC87">6.8.1 Directory Stack Builtins</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX102"><CODE>printf</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC60">4.2 Bash Builtin Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX292"><CODE>pushd</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC87">6.8.1 Directory Stack Builtins</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX79"><CODE>pwd</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC59">4.1 Bourne Shell Builtins</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="bt_R"></A>R</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX103"><CODE>read</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC60">4.2 Bash Builtin Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX104"><CODE>readarray</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC60">4.2 Bash Builtin Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX80"><CODE>readonly</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC59">4.1 Bourne Shell Builtins</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX81"><CODE>return</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC59">4.1 Bourne Shell Builtins</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="bt_S"></A>S</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX110"><CODE>set</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC62">4.3.1 The Set Builtin</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX82"><CODE>shift</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC59">4.1 Bourne Shell Builtins</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX111"><CODE>shopt</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC63">4.3.2 The Shopt Builtin</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX105"><CODE>source</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC60">4.2 Bash Builtin Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX299"><CODE>suspend</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC93">7.2 Job Control Builtins</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="bt_T"></A>T</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX83"><CODE>test</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC59">4.1 Bourne Shell Builtins</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX85"><CODE>times</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC59">4.1 Bourne Shell Builtins</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX86"><CODE>trap</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC59">4.1 Bourne Shell Builtins</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX106"><CODE>type</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC60">4.2 Bash Builtin Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX107"><CODE>typeset</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC60">4.2 Bash Builtin Commands</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="bt_U"></A>U</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX108"><CODE>ulimit</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC60">4.2 Bash Builtin Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX87"><CODE>umask</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC59">4.1 Bourne Shell Builtins</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX109"><CODE>unalias</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC60">4.2 Bash Builtin Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX88"><CODE>unset</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC59">4.1 Bourne Shell Builtins</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="bt_W"></A>W</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX297"><CODE>wait</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC93">7.2 Job Control Builtins</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +</TABLE><P></P><table><tr><th valign=top>Jump to: </th><td><A HREF="bashref.html#bt_." style="text-decoration:none"><b>.</b></A> + +<A HREF="bashref.html#bt_:" style="text-decoration:none"><b>:</b></A> + +<A HREF="bashref.html#bt_[" style="text-decoration:none"><b>[</b></A> + +<BR> +<A HREF="bashref.html#bt_A" style="text-decoration:none"><b>A</b></A> + +<A HREF="bashref.html#bt_B" style="text-decoration:none"><b>B</b></A> + +<A HREF="bashref.html#bt_C" style="text-decoration:none"><b>C</b></A> + +<A HREF="bashref.html#bt_D" style="text-decoration:none"><b>D</b></A> + +<A HREF="bashref.html#bt_E" style="text-decoration:none"><b>E</b></A> + +<A HREF="bashref.html#bt_F" style="text-decoration:none"><b>F</b></A> + +<A HREF="bashref.html#bt_G" style="text-decoration:none"><b>G</b></A> + +<A HREF="bashref.html#bt_H" style="text-decoration:none"><b>H</b></A> + +<A HREF="bashref.html#bt_J" style="text-decoration:none"><b>J</b></A> + +<A HREF="bashref.html#bt_K" style="text-decoration:none"><b>K</b></A> + +<A HREF="bashref.html#bt_L" style="text-decoration:none"><b>L</b></A> + +<A HREF="bashref.html#bt_M" style="text-decoration:none"><b>M</b></A> + +<A HREF="bashref.html#bt_P" style="text-decoration:none"><b>P</b></A> + +<A HREF="bashref.html#bt_R" style="text-decoration:none"><b>R</b></A> + +<A HREF="bashref.html#bt_S" style="text-decoration:none"><b>S</b></A> + +<A HREF="bashref.html#bt_T" style="text-decoration:none"><b>T</b></A> + +<A HREF="bashref.html#bt_U" style="text-decoration:none"><b>U</b></A> + +<A HREF="bashref.html#bt_W" style="text-decoration:none"><b>W</b></A> + +</td></tr></table><br><P> + +<A NAME="Reserved Word Index"></A> +<HR SIZE="6"> +<A NAME="SEC142"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC141"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC143"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC143"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[ >> ]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H2> D.2 Index of Shell Reserved Words </H2> +<!--docid::SEC142::--> +<table><tr><th valign=top>Jump to: </th><td><A HREF="bashref.html#rw_!" style="text-decoration:none"><b>!</b></A> + +<A HREF="bashref.html#rw_[" style="text-decoration:none"><b>[</b></A> + +<A HREF="bashref.html#rw_]" style="text-decoration:none"><b>]</b></A> + +<A HREF="bashref.html#rw_{" style="text-decoration:none"><b>{</b></A> + +<A HREF="bashref.html#rw_}" style="text-decoration:none"><b>}</b></A> + +<BR> +<A HREF="bashref.html#rw_C" style="text-decoration:none"><b>C</b></A> + +<A HREF="bashref.html#rw_D" style="text-decoration:none"><b>D</b></A> + +<A HREF="bashref.html#rw_E" style="text-decoration:none"><b>E</b></A> + +<A HREF="bashref.html#rw_F" style="text-decoration:none"><b>F</b></A> + +<A HREF="bashref.html#rw_I" style="text-decoration:none"><b>I</b></A> + +<A HREF="bashref.html#rw_S" style="text-decoration:none"><b>S</b></A> + +<A HREF="bashref.html#rw_T" style="text-decoration:none"><b>T</b></A> + +<A HREF="bashref.html#rw_U" style="text-decoration:none"><b>U</b></A> + +<A HREF="bashref.html#rw_W" style="text-decoration:none"><b>W</b></A> + +</td></tr></table><br><P></P> +<TABLE border=0> +<TR><TD></TD><TH ALIGN=LEFT>Index Entry</TH><TH ALIGN=LEFT> Section</TH></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="rw_!"></A>!</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX25"><CODE>!</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC17">3.2.2 Pipelines</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="rw_["></A>[</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX41"><CODE>[[</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC21">3.2.4.2 Conditional Constructs</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="rw_]"></A>]</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX42"><CODE>]]</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC21">3.2.4.2 Conditional Constructs</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="rw_{"></A>{</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX43"><CODE>{</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC22">3.2.4.3 Grouping Commands</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="rw_}"></A>}</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX44"><CODE>}</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC22">3.2.4.3 Grouping Commands</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="rw_C"></A>C</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX37"><CODE>case</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC21">3.2.4.2 Conditional Constructs</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="rw_D"></A>D</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX28"><CODE>do</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC20">3.2.4.1 Looping Constructs</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX29"><CODE>done</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC20">3.2.4.1 Looping Constructs</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="rw_E"></A>E</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX35"><CODE>elif</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC21">3.2.4.2 Conditional Constructs</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX34"><CODE>else</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC21">3.2.4.2 Conditional Constructs</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX39"><CODE>esac</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC21">3.2.4.2 Conditional Constructs</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="rw_F"></A>F</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX36"><CODE>fi</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC21">3.2.4.2 Conditional Constructs</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX31"><CODE>for</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC20">3.2.4.1 Looping Constructs</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX45"><CODE>function</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC24">3.3 Shell Functions</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="rw_I"></A>I</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX32"><CODE>if</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC21">3.2.4.2 Conditional Constructs</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX38"><CODE>in</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC21">3.2.4.2 Conditional Constructs</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="rw_S"></A>S</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX40"><CODE>select</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC21">3.2.4.2 Conditional Constructs</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="rw_T"></A>T</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX33"><CODE>then</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC21">3.2.4.2 Conditional Constructs</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX24"><CODE>time</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC17">3.2.2 Pipelines</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="rw_U"></A>U</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX27"><CODE>until</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC20">3.2.4.1 Looping Constructs</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="rw_W"></A>W</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX30"><CODE>while</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC20">3.2.4.1 Looping Constructs</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +</TABLE><P></P><table><tr><th valign=top>Jump to: </th><td><A HREF="bashref.html#rw_!" style="text-decoration:none"><b>!</b></A> + +<A HREF="bashref.html#rw_[" style="text-decoration:none"><b>[</b></A> + +<A HREF="bashref.html#rw_]" style="text-decoration:none"><b>]</b></A> + +<A HREF="bashref.html#rw_{" style="text-decoration:none"><b>{</b></A> + +<A HREF="bashref.html#rw_}" style="text-decoration:none"><b>}</b></A> + +<BR> +<A HREF="bashref.html#rw_C" style="text-decoration:none"><b>C</b></A> + +<A HREF="bashref.html#rw_D" style="text-decoration:none"><b>D</b></A> + +<A HREF="bashref.html#rw_E" style="text-decoration:none"><b>E</b></A> + +<A HREF="bashref.html#rw_F" style="text-decoration:none"><b>F</b></A> + +<A HREF="bashref.html#rw_I" style="text-decoration:none"><b>I</b></A> + +<A HREF="bashref.html#rw_S" style="text-decoration:none"><b>S</b></A> + +<A HREF="bashref.html#rw_T" style="text-decoration:none"><b>T</b></A> + +<A HREF="bashref.html#rw_U" style="text-decoration:none"><b>U</b></A> + +<A HREF="bashref.html#rw_W" style="text-decoration:none"><b>W</b></A> + +</td></tr></table><br><P> + +<A NAME="Variable Index"></A> +<HR SIZE="6"> +<A NAME="SEC143"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC142"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC144"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC144"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[ >> ]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H2> D.3 Parameter and Variable Index </H2> +<!--docid::SEC143::--> +<table><tr><th valign=top>Jump to: </th><td><A HREF="bashref.html#vr_!" style="text-decoration:none"><b>!</b></A> + +<A HREF="bashref.html#vr_#" style="text-decoration:none"><b>#</b></A> + +<A HREF="bashref.html#vr_$" style="text-decoration:none"><b>$</b></A> + +<A HREF="bashref.html#vr_*" style="text-decoration:none"><b>*</b></A> + +<A HREF="bashref.html#vr_-" style="text-decoration:none"><b>-</b></A> + +<A HREF="bashref.html#vr_0" style="text-decoration:none"><b>0</b></A> + +<A HREF="bashref.html#vr_?" style="text-decoration:none"><b>?</b></A> + +<A HREF="bashref.html#vr_@" style="text-decoration:none"><b>@</b></A> + +<A HREF="bashref.html#vr__" style="text-decoration:none"><b>_</b></A> + +<BR> +<A HREF="bashref.html#vr_A" style="text-decoration:none"><b>A</b></A> + +<A HREF="bashref.html#vr_B" style="text-decoration:none"><b>B</b></A> + +<A HREF="bashref.html#vr_C" style="text-decoration:none"><b>C</b></A> + +<A HREF="bashref.html#vr_D" style="text-decoration:none"><b>D</b></A> + +<A HREF="bashref.html#vr_E" style="text-decoration:none"><b>E</b></A> + +<A HREF="bashref.html#vr_F" style="text-decoration:none"><b>F</b></A> + +<A HREF="bashref.html#vr_G" style="text-decoration:none"><b>G</b></A> + +<A HREF="bashref.html#vr_H" style="text-decoration:none"><b>H</b></A> + +<A HREF="bashref.html#vr_I" style="text-decoration:none"><b>I</b></A> + +<A HREF="bashref.html#vr_K" style="text-decoration:none"><b>K</b></A> + +<A HREF="bashref.html#vr_L" style="text-decoration:none"><b>L</b></A> + +<A HREF="bashref.html#vr_M" style="text-decoration:none"><b>M</b></A> + +<A HREF="bashref.html#vr_O" style="text-decoration:none"><b>O</b></A> + +<A HREF="bashref.html#vr_P" style="text-decoration:none"><b>P</b></A> + +<A HREF="bashref.html#vr_R" style="text-decoration:none"><b>R</b></A> + +<A HREF="bashref.html#vr_S" style="text-decoration:none"><b>S</b></A> + +<A HREF="bashref.html#vr_T" style="text-decoration:none"><b>T</b></A> + +<A HREF="bashref.html#vr_U" style="text-decoration:none"><b>U</b></A> + +<A HREF="bashref.html#vr_V" style="text-decoration:none"><b>V</b></A> + +</td></tr></table><br><P></P> +<TABLE border=0> +<TR><TD></TD><TH ALIGN=LEFT>Index Entry</TH><TH ALIGN=LEFT> Section</TH></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="vr_!"></A>!</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX58"><CODE>!</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC27">3.4.2 Special Parameters</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX59"><CODE>!</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC27">3.4.2 Special Parameters</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="vr_#"></A>#</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX50"><CODE>#</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC27">3.4.2 Special Parameters</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX51"><CODE>#</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC27">3.4.2 Special Parameters</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="vr_$"></A>$</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX56"><CODE>$</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC27">3.4.2 Special Parameters</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX57"><CODE>$</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC27">3.4.2 Special Parameters</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="vr_*"></A>*</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX46"><CODE>*</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC27">3.4.2 Special Parameters</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX47"><CODE>*</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC27">3.4.2 Special Parameters</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="vr_-"></A>-</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX54"><CODE>-</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC27">3.4.2 Special Parameters</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX55"><CODE>-</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC27">3.4.2 Special Parameters</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="vr_0"></A>0</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX60"><CODE>0</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC27">3.4.2 Special Parameters</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX61"><CODE>0</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC27">3.4.2 Special Parameters</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="vr_?"></A>?</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX52"><CODE>?</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC27">3.4.2 Special Parameters</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX53"><CODE>?</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC27">3.4.2 Special Parameters</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="vr_@"></A>@</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX48"><CODE>@</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC27">3.4.2 Special Parameters</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX49"><CODE>@</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC27">3.4.2 Special Parameters</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="vr__"></A>_</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX62"><CODE>_</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC27">3.4.2 Special Parameters</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX63"><CODE>_</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC27">3.4.2 Special Parameters</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="vr_A"></A>A</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX300"><CODE>auto_resume</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC94">7.3 Job Control Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX301"><CODE>auto_resume</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC94">7.3 Job Control Variables</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="vr_B"></A>B</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX132"><CODE>BASH</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX133"><CODE>BASH</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX138"><CODE>BASH_ALIASES</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX139"><CODE>BASH_ALIASES</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX140"><CODE>BASH_ARGC</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX141"><CODE>BASH_ARGC</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX142"><CODE>BASH_ARGV</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX143"><CODE>BASH_ARGV</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX144"><CODE>BASH_CMDS</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX145"><CODE>BASH_CMDS</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX146"><CODE>BASH_COMMAND</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX147"><CODE>BASH_COMMAND</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX148"><CODE>BASH_ENV</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX149"><CODE>BASH_ENV</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX150"><CODE>BASH_EXECUTION_STRING</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX151"><CODE>BASH_EXECUTION_STRING</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX152"><CODE>BASH_LINENO</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX153"><CODE>BASH_LINENO</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX154"><CODE>BASH_REMATCH</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX155"><CODE>BASH_REMATCH</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX156"><CODE>BASH_SOURCE</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX157"><CODE>BASH_SOURCE</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX158"><CODE>BASH_SUBSHELL</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX159"><CODE>BASH_SUBSHELL</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX160"><CODE>BASH_VERSINFO</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX161"><CODE>BASH_VERSINFO</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX162"><CODE>BASH_VERSION</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX163"><CODE>BASH_VERSION</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX164"><CODE>BASH_XTRACEFD</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX165"><CODE>BASH_XTRACEFD</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX134"><CODE>BASHOPTS</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX135"><CODE>BASHOPTS</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX136"><CODE>BASHPID</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX137"><CODE>BASHPID</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX307"><CODE>bell-style</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC104">8.3.1 Readline Init File Syntax</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX308"><CODE>bind-tty-special-chars</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC104">8.3.1 Readline Init File Syntax</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="vr_C"></A>C</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX112"><CODE>CDPATH</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC66">5.1 Bourne Shell Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX113"><CODE>CDPATH</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC66">5.1 Bourne Shell Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX166"><CODE>COLUMNS</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX167"><CODE>COLUMNS</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX309"><CODE>comment-begin</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC104">8.3.1 Readline Init File Syntax</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX168"><CODE>COMP_CWORD</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX169"><CODE>COMP_CWORD</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX176"><CODE>COMP_KEY</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX177"><CODE>COMP_KEY</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX170"><CODE>COMP_LINE</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX171"><CODE>COMP_LINE</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX172"><CODE>COMP_POINT</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX173"><CODE>COMP_POINT</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX174"><CODE>COMP_TYPE</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX175"><CODE>COMP_TYPE</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX178"><CODE>COMP_WORDBREAKS</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX179"><CODE>COMP_WORDBREAKS</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX180"><CODE>COMP_WORDS</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX181"><CODE>COMP_WORDS</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX310"><CODE>completion-prefix-display-length</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC104">8.3.1 Readline Init File Syntax</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX311"><CODE>completion-query-items</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC104">8.3.1 Readline Init File Syntax</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX182"><CODE>COMPREPLY</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX183"><CODE>COMPREPLY</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX312"><CODE>convert-meta</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC104">8.3.1 Readline Init File Syntax</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="vr_D"></A>D</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX184"><CODE>DIRSTACK</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX185"><CODE>DIRSTACK</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX313"><CODE>disable-completion</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC104">8.3.1 Readline Init File Syntax</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="vr_E"></A>E</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX314"><CODE>editing-mode</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC104">8.3.1 Readline Init File Syntax</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX186"><CODE>EMACS</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX187"><CODE>EMACS</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX315"><CODE>enable-keypad</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC104">8.3.1 Readline Init File Syntax</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX188"><CODE>EUID</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX189"><CODE>EUID</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX316"><CODE>expand-tilde</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC104">8.3.1 Readline Init File Syntax</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="vr_F"></A>F</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX190"><CODE>FCEDIT</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX191"><CODE>FCEDIT</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX192"><CODE>FIGNORE</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX193"><CODE>FIGNORE</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX194"><CODE>FUNCNAME</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX195"><CODE>FUNCNAME</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="vr_G"></A>G</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX196"><CODE>GLOBIGNORE</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX197"><CODE>GLOBIGNORE</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX198"><CODE>GROUPS</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX199"><CODE>GROUPS</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="vr_H"></A>H</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX200"><CODE>histchars</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX201"><CODE>histchars</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX202"><CODE>HISTCMD</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX203"><CODE>HISTCMD</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX204"><CODE>HISTCONTROL</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX205"><CODE>HISTCONTROL</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX206"><CODE>HISTFILE</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX207"><CODE>HISTFILE</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX208"><CODE>HISTFILESIZE</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX209"><CODE>HISTFILESIZE</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX210"><CODE>HISTIGNORE</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX211"><CODE>HISTIGNORE</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX317"><CODE>history-preserve-point</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC104">8.3.1 Readline Init File Syntax</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX318"><CODE>history-size</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC104">8.3.1 Readline Init File Syntax</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX212"><CODE>HISTSIZE</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX213"><CODE>HISTSIZE</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX214"><CODE>HISTTIMEFORMAT</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX215"><CODE>HISTTIMEFORMAT</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX114"><CODE>HOME</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC66">5.1 Bourne Shell Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX115"><CODE>HOME</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC66">5.1 Bourne Shell Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX319"><CODE>horizontal-scroll-mode</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC104">8.3.1 Readline Init File Syntax</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX216"><CODE>HOSTFILE</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX217"><CODE>HOSTFILE</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX218"><CODE>HOSTNAME</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX219"><CODE>HOSTNAME</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX220"><CODE>HOSTTYPE</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX221"><CODE>HOSTTYPE</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="vr_I"></A>I</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX116"><CODE>IFS</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC66">5.1 Bourne Shell Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX117"><CODE>IFS</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC66">5.1 Bourne Shell Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX222"><CODE>IGNOREEOF</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX223"><CODE>IGNOREEOF</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX320"><CODE>input-meta</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC104">8.3.1 Readline Init File Syntax</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX224"><CODE>INPUTRC</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX225"><CODE>INPUTRC</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX322"><CODE>isearch-terminators</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC104">8.3.1 Readline Init File Syntax</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="vr_K"></A>K</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX323"><CODE>keymap</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC104">8.3.1 Readline Init File Syntax</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="vr_L"></A>L</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX226"><CODE>LANG</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX227"><CODE>LANG</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX228"><CODE>LC_ALL</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX229"><CODE>LC_ALL</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX230"><CODE>LC_COLLATE</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX231"><CODE>LC_COLLATE</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX232"><CODE>LC_CTYPE</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX233"><CODE>LC_CTYPE</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX21"><CODE>LC_MESSAGES</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC13">3.1.2.5 Locale-Specific Translation</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX234"><CODE>LC_MESSAGES</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX235"><CODE>LC_MESSAGES</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX236"><CODE>LC_NUMERIC</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX237"><CODE>LC_NUMERIC</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX238"><CODE>LINENO</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX239"><CODE>LINENO</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX240"><CODE>LINES</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX241"><CODE>LINES</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="vr_M"></A>M</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX242"><CODE>MACHTYPE</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX243"><CODE>MACHTYPE</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX118"><CODE>MAIL</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC66">5.1 Bourne Shell Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX119"><CODE>MAIL</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC66">5.1 Bourne Shell Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX244"><CODE>MAILCHECK</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX245"><CODE>MAILCHECK</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX120"><CODE>MAILPATH</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC66">5.1 Bourne Shell Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX121"><CODE>MAILPATH</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC66">5.1 Bourne Shell Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX324"><CODE>mark-modified-lines</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC104">8.3.1 Readline Init File Syntax</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX325"><CODE>mark-symlinked-directories</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC104">8.3.1 Readline Init File Syntax</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX326"><CODE>match-hidden-files</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC104">8.3.1 Readline Init File Syntax</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX321"><CODE>meta-flag</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC104">8.3.1 Readline Init File Syntax</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="vr_O"></A>O</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX246"><CODE>OLDPWD</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX247"><CODE>OLDPWD</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX122"><CODE>OPTARG</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC66">5.1 Bourne Shell Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX123"><CODE>OPTARG</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC66">5.1 Bourne Shell Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX248"><CODE>OPTERR</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX249"><CODE>OPTERR</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX124"><CODE>OPTIND</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC66">5.1 Bourne Shell Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX125"><CODE>OPTIND</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC66">5.1 Bourne Shell Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX250"><CODE>OSTYPE</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX251"><CODE>OSTYPE</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX327"><CODE>output-meta</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC104">8.3.1 Readline Init File Syntax</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="vr_P"></A>P</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX328"><CODE>page-completions</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC104">8.3.1 Readline Init File Syntax</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX126"><CODE>PATH</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC66">5.1 Bourne Shell Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX127"><CODE>PATH</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC66">5.1 Bourne Shell Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX252"><CODE>PIPESTATUS</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX253"><CODE>PIPESTATUS</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX254"><CODE>POSIXLY_CORRECT</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX255"><CODE>POSIXLY_CORRECT</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX256"><CODE>PPID</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX257"><CODE>PPID</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX258"><CODE>PROMPT_COMMAND</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX259"><CODE>PROMPT_COMMAND</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX260"><CODE>PROMPT_DIRTRIM</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX261"><CODE>PROMPT_DIRTRIM</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX128"><CODE>PS1</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC66">5.1 Bourne Shell Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX129"><CODE>PS1</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC66">5.1 Bourne Shell Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX130"><CODE>PS2</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC66">5.1 Bourne Shell Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX131"><CODE>PS2</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC66">5.1 Bourne Shell Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX262"><CODE>PS3</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX263"><CODE>PS3</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX264"><CODE>PS4</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX265"><CODE>PS4</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX266"><CODE>PWD</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX267"><CODE>PWD</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="vr_R"></A>R</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX268"><CODE>RANDOM</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX269"><CODE>RANDOM</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX270"><CODE>REPLY</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX271"><CODE>REPLY</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX329"><CODE>revert-all-at-newline</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC104">8.3.1 Readline Init File Syntax</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="vr_S"></A>S</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX272"><CODE>SECONDS</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX273"><CODE>SECONDS</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX274"><CODE>SHELL</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX275"><CODE>SHELL</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX276"><CODE>SHELLOPTS</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX277"><CODE>SHELLOPTS</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX278"><CODE>SHLVL</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX279"><CODE>SHLVL</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX330"><CODE>show-all-if-ambiguous</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC104">8.3.1 Readline Init File Syntax</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX331"><CODE>show-all-if-unmodified</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC104">8.3.1 Readline Init File Syntax</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX332"><CODE>skip-completed-text</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC104">8.3.1 Readline Init File Syntax</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="vr_T"></A>T</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX22"><CODE>TEXTDOMAIN</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC13">3.1.2.5 Locale-Specific Translation</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX23"><CODE>TEXTDOMAINDIR</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC13">3.1.2.5 Locale-Specific Translation</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX280"><CODE>TIMEFORMAT</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX281"><CODE>TIMEFORMAT</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX282"><CODE>TMOUT</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX283"><CODE>TMOUT</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX284"><CODE>TMPDIR</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX285"><CODE>TMPDIR</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="vr_U"></A>U</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX286"><CODE>UID</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX287"><CODE>UID</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC67">5.2 Bash Variables</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="vr_V"></A>V</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX333"><CODE>visible-stats</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC104">8.3.1 Readline Init File Syntax</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +</TABLE><P></P><table><tr><th valign=top>Jump to: </th><td><A HREF="bashref.html#vr_!" style="text-decoration:none"><b>!</b></A> + +<A HREF="bashref.html#vr_#" style="text-decoration:none"><b>#</b></A> + +<A HREF="bashref.html#vr_$" style="text-decoration:none"><b>$</b></A> + +<A HREF="bashref.html#vr_*" style="text-decoration:none"><b>*</b></A> + +<A HREF="bashref.html#vr_-" style="text-decoration:none"><b>-</b></A> + +<A HREF="bashref.html#vr_0" style="text-decoration:none"><b>0</b></A> + +<A HREF="bashref.html#vr_?" style="text-decoration:none"><b>?</b></A> + +<A HREF="bashref.html#vr_@" style="text-decoration:none"><b>@</b></A> + +<A HREF="bashref.html#vr__" style="text-decoration:none"><b>_</b></A> + +<BR> +<A HREF="bashref.html#vr_A" style="text-decoration:none"><b>A</b></A> + +<A HREF="bashref.html#vr_B" style="text-decoration:none"><b>B</b></A> + +<A HREF="bashref.html#vr_C" style="text-decoration:none"><b>C</b></A> + +<A HREF="bashref.html#vr_D" style="text-decoration:none"><b>D</b></A> + +<A HREF="bashref.html#vr_E" style="text-decoration:none"><b>E</b></A> + +<A HREF="bashref.html#vr_F" style="text-decoration:none"><b>F</b></A> + +<A HREF="bashref.html#vr_G" style="text-decoration:none"><b>G</b></A> + +<A HREF="bashref.html#vr_H" style="text-decoration:none"><b>H</b></A> + +<A HREF="bashref.html#vr_I" style="text-decoration:none"><b>I</b></A> + +<A HREF="bashref.html#vr_K" style="text-decoration:none"><b>K</b></A> + +<A HREF="bashref.html#vr_L" style="text-decoration:none"><b>L</b></A> + +<A HREF="bashref.html#vr_M" style="text-decoration:none"><b>M</b></A> + +<A HREF="bashref.html#vr_O" style="text-decoration:none"><b>O</b></A> + +<A HREF="bashref.html#vr_P" style="text-decoration:none"><b>P</b></A> + +<A HREF="bashref.html#vr_R" style="text-decoration:none"><b>R</b></A> + +<A HREF="bashref.html#vr_S" style="text-decoration:none"><b>S</b></A> + +<A HREF="bashref.html#vr_T" style="text-decoration:none"><b>T</b></A> + +<A HREF="bashref.html#vr_U" style="text-decoration:none"><b>U</b></A> + +<A HREF="bashref.html#vr_V" style="text-decoration:none"><b>V</b></A> + +</td></tr></table><br><P> + +<A NAME="Function Index"></A> +<HR SIZE="6"> +<A NAME="SEC144"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC143"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC145"> > </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC145"> << </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[ >> ]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H2> D.4 Function Index </H2> +<!--docid::SEC144::--> +<table><tr><th valign=top>Jump to: </th><td><A HREF="bashref.html#fn_A" style="text-decoration:none"><b>A</b></A> + +<A HREF="bashref.html#fn_B" style="text-decoration:none"><b>B</b></A> + +<A HREF="bashref.html#fn_C" style="text-decoration:none"><b>C</b></A> + +<A HREF="bashref.html#fn_D" style="text-decoration:none"><b>D</b></A> + +<A HREF="bashref.html#fn_E" style="text-decoration:none"><b>E</b></A> + +<A HREF="bashref.html#fn_F" style="text-decoration:none"><b>F</b></A> + +<A HREF="bashref.html#fn_G" style="text-decoration:none"><b>G</b></A> + +<A HREF="bashref.html#fn_H" style="text-decoration:none"><b>H</b></A> + +<A HREF="bashref.html#fn_I" style="text-decoration:none"><b>I</b></A> + +<A HREF="bashref.html#fn_K" style="text-decoration:none"><b>K</b></A> + +<A HREF="bashref.html#fn_M" style="text-decoration:none"><b>M</b></A> + +<A HREF="bashref.html#fn_N" style="text-decoration:none"><b>N</b></A> + +<A HREF="bashref.html#fn_O" style="text-decoration:none"><b>O</b></A> + +<A HREF="bashref.html#fn_P" style="text-decoration:none"><b>P</b></A> + +<A HREF="bashref.html#fn_Q" style="text-decoration:none"><b>Q</b></A> + +<A HREF="bashref.html#fn_R" style="text-decoration:none"><b>R</b></A> + +<A HREF="bashref.html#fn_S" style="text-decoration:none"><b>S</b></A> + +<A HREF="bashref.html#fn_T" style="text-decoration:none"><b>T</b></A> + +<A HREF="bashref.html#fn_U" style="text-decoration:none"><b>U</b></A> + +<A HREF="bashref.html#fn_Y" style="text-decoration:none"><b>Y</b></A> + +</td></tr></table><br><P></P> +<TABLE border=0> +<TR><TD></TD><TH ALIGN=LEFT>Index Entry</TH><TH ALIGN=LEFT> Section</TH></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="fn_A"></A>A</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX486"><CODE>abort (C-g)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC115">8.4.8 Some Miscellaneous Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX487"><CODE>abort (C-g)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC115">8.4.8 Some Miscellaneous Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX354"><CODE>accept-line (Newline or Return)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC109">8.4.2 Commands For Manipulating The History</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX355"><CODE>accept-line (Newline or Return)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC109">8.4.2 Commands For Manipulating The History</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX530"><CODE>alias-expand-line ()</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC115">8.4.8 Some Miscellaneous Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX531"><CODE>alias-expand-line ()</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC115">8.4.8 Some Miscellaneous Commands</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="fn_B"></A>B</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX340"><CODE>backward-char (C-b)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC108">8.4.1 Commands For Moving</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX341"><CODE>backward-char (C-b)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC108">8.4.1 Commands For Moving</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX382"><CODE>backward-delete-char (Rubout)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC110">8.4.3 Commands For Changing Text</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX383"><CODE>backward-delete-char (Rubout)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC110">8.4.3 Commands For Changing Text</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX404"><CODE>backward-kill-line (C-x Rubout)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC111">8.4.4 Killing And Yanking</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX405"><CODE>backward-kill-line (C-x Rubout)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC111">8.4.4 Killing And Yanking</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX416"><CODE>backward-kill-word ()</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC111">8.4.4 Killing And Yanking</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX417"><CODE>backward-kill-word ()</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC111">8.4.4 Killing And Yanking</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX412"><CODE>backward-kill-word (M-<KBD>DEL</KBD>)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC111">8.4.4 Killing And Yanking</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX413"><CODE>backward-kill-word (M-<KBD>DEL</KBD>)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC111">8.4.4 Killing And Yanking</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX344"><CODE>backward-word (M-b)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC108">8.4.1 Commands For Moving</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX345"><CODE>backward-word (M-b)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC108">8.4.1 Commands For Moving</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX360"><CODE>beginning-of-history (M-&#60;)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC109">8.4.2 Commands For Manipulating The History</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX361"><CODE>beginning-of-history (M-&#60;)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC109">8.4.2 Commands For Manipulating The History</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX334"><CODE>beginning-of-line (C-a)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC108">8.4.1 Commands For Moving</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX335"><CODE>beginning-of-line (C-a)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC108">8.4.1 Commands For Moving</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="fn_C"></A>C</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX482"><CODE>call-last-kbd-macro (C-x e)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC114">8.4.7 Keyboard Macros</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX483"><CODE>call-last-kbd-macro (C-x e)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC114">8.4.7 Keyboard Macros</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX398"><CODE>capitalize-word (M-c)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC110">8.4.3 Commands For Changing Text</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX399"><CODE>capitalize-word (M-c)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC110">8.4.3 Commands For Changing Text</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX502"><CODE>character-search (C-])</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC115">8.4.8 Some Miscellaneous Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX503"><CODE>character-search (C-])</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC115">8.4.8 Some Miscellaneous Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX504"><CODE>character-search-backward (M-C-])</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC115">8.4.8 Some Miscellaneous Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX505"><CODE>character-search-backward (M-C-])</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC115">8.4.8 Some Miscellaneous Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX350"><CODE>clear-screen (C-l)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC108">8.4.1 Commands For Moving</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX351"><CODE>clear-screen (C-l)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC108">8.4.1 Commands For Moving</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX440"><CODE>complete (<KBD>TAB</KBD>)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC113">8.4.6 Letting Readline Type For You</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX441"><CODE>complete (<KBD>TAB</KBD>)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC113">8.4.6 Letting Readline Type For You</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX468"><CODE>complete-command (M-!)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC113">8.4.6 Letting Readline Type For You</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX469"><CODE>complete-command (M-!)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC113">8.4.6 Letting Readline Type For You</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX452"><CODE>complete-filename (M-/)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC113">8.4.6 Letting Readline Type For You</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX453"><CODE>complete-filename (M-/)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC113">8.4.6 Letting Readline Type For You</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX464"><CODE>complete-hostname (M-@)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC113">8.4.6 Letting Readline Type For You</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX465"><CODE>complete-hostname (M-@)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC113">8.4.6 Letting Readline Type For You</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX476"><CODE>complete-into-braces (M-{)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC113">8.4.6 Letting Readline Type For You</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX477"><CODE>complete-into-braces (M-{)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC113">8.4.6 Letting Readline Type For You</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX456"><CODE>complete-username (M-~)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC113">8.4.6 Letting Readline Type For You</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX457"><CODE>complete-username (M-~)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC113">8.4.6 Letting Readline Type For You</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX460"><CODE>complete-variable (M-$)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC113">8.4.6 Letting Readline Type For You</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX461"><CODE>complete-variable (M-$)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC113">8.4.6 Letting Readline Type For You</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX428"><CODE>copy-backward-word ()</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC111">8.4.4 Killing And Yanking</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX429"><CODE>copy-backward-word ()</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC111">8.4.4 Killing And Yanking</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX430"><CODE>copy-forward-word ()</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC111">8.4.4 Killing And Yanking</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX431"><CODE>copy-forward-word ()</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC111">8.4.4 Killing And Yanking</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX426"><CODE>copy-region-as-kill ()</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC111">8.4.4 Killing And Yanking</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX427"><CODE>copy-region-as-kill ()</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC111">8.4.4 Killing And Yanking</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="fn_D"></A>D</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX474"><CODE>dabbrev-expand ()</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC113">8.4.6 Letting Readline Type For You</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX475"><CODE>dabbrev-expand ()</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC113">8.4.6 Letting Readline Type For You</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX380"><CODE>delete-char (C-d)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC110">8.4.3 Commands For Changing Text</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX381"><CODE>delete-char (C-d)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC110">8.4.3 Commands For Changing Text</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX450"><CODE>delete-char-or-list ()</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC113">8.4.6 Letting Readline Type For You</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX451"><CODE>delete-char-or-list ()</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC113">8.4.6 Letting Readline Type For You</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX422"><CODE>delete-horizontal-space ()</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC111">8.4.4 Killing And Yanking</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX423"><CODE>delete-horizontal-space ()</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC111">8.4.4 Killing And Yanking</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX436"><CODE>digit-argument (<KBD>M-0</KBD>, <KBD>M-1</KBD>, <small>...</small> <KBD>M--</KBD>)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC112">8.4.5 Specifying Numeric Arguments</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX437"><CODE>digit-argument (<KBD>M-0</KBD>, <KBD>M-1</KBD>, <small>...</small> <KBD>M--</KBD>)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC112">8.4.5 Specifying Numeric Arguments</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX522"><CODE>display-shell-version (C-x C-v)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC115">8.4.8 Some Miscellaneous Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX523"><CODE>display-shell-version (C-x C-v)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC115">8.4.8 Some Miscellaneous Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX488"><CODE>do-uppercase-version (M-a, M-b, M-<VAR>x</VAR>, <small>...</small>)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC115">8.4.8 Some Miscellaneous Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX489"><CODE>do-uppercase-version (M-a, M-b, M-<VAR>x</VAR>, <small>...</small>)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC115">8.4.8 Some Miscellaneous Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX396"><CODE>downcase-word (M-l)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC110">8.4.3 Commands For Changing Text</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX397"><CODE>downcase-word (M-l)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC110">8.4.3 Commands For Changing Text</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX510"><CODE>dump-functions ()</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC115">8.4.8 Some Miscellaneous Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX511"><CODE>dump-functions ()</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC115">8.4.8 Some Miscellaneous Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX514"><CODE>dump-macros ()</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC115">8.4.8 Some Miscellaneous Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX515"><CODE>dump-macros ()</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC115">8.4.8 Some Miscellaneous Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX512"><CODE>dump-variables ()</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC115">8.4.8 Some Miscellaneous Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX513"><CODE>dump-variables ()</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC115">8.4.8 Some Miscellaneous Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX472"><CODE>dynamic-complete-history (M-<KBD>TAB</KBD>)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC113">8.4.6 Letting Readline Type For You</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX473"><CODE>dynamic-complete-history (M-<KBD>TAB</KBD>)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC113">8.4.6 Letting Readline Type For You</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="fn_E"></A>E</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX538"><CODE>edit-and-execute-command (C-xC-e)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC115">8.4.8 Some Miscellaneous Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX539"><CODE>edit-and-execute-command (C-xC-e)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC115">8.4.8 Some Miscellaneous Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX480"><CODE>end-kbd-macro (C-x ))</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC114">8.4.7 Keyboard Macros</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX481"><CODE>end-kbd-macro (C-x ))</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC114">8.4.7 Keyboard Macros</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX362"><CODE>end-of-history (M-&#62;)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC109">8.4.2 Commands For Manipulating The History</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX363"><CODE>end-of-history (M-&#62;)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC109">8.4.2 Commands For Manipulating The History</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX336"><CODE>end-of-line (C-e)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC108">8.4.1 Commands For Moving</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX337"><CODE>end-of-line (C-e)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC108">8.4.1 Commands For Moving</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX500"><CODE>exchange-point-and-mark (C-x C-x)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC115">8.4.8 Some Miscellaneous Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX501"><CODE>exchange-point-and-mark (C-x C-x)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC115">8.4.8 Some Miscellaneous Commands</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="fn_F"></A>F</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX384"><CODE>forward-backward-delete-char ()</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC110">8.4.3 Commands For Changing Text</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX385"><CODE>forward-backward-delete-char ()</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC110">8.4.3 Commands For Changing Text</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX338"><CODE>forward-char (C-f)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC108">8.4.1 Commands For Moving</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX339"><CODE>forward-char (C-f)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC108">8.4.1 Commands For Moving</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX366"><CODE>forward-search-history (C-s)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC109">8.4.2 Commands For Manipulating The History</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX367"><CODE>forward-search-history (C-s)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC109">8.4.2 Commands For Manipulating The History</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX342"><CODE>forward-word (M-f)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC108">8.4.1 Commands For Moving</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX343"><CODE>forward-word (M-f)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC108">8.4.1 Commands For Moving</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="fn_G"></A>G</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX516"><CODE>glob-complete-word (M-g)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC115">8.4.8 Some Miscellaneous Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX517"><CODE>glob-complete-word (M-g)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC115">8.4.8 Some Miscellaneous Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX518"><CODE>glob-expand-word (C-x *)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC115">8.4.8 Some Miscellaneous Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX519"><CODE>glob-expand-word (C-x *)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC115">8.4.8 Some Miscellaneous Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX520"><CODE>glob-list-expansions (C-x g)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC115">8.4.8 Some Miscellaneous Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX521"><CODE>glob-list-expansions (C-x g)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC115">8.4.8 Some Miscellaneous Commands</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="fn_H"></A>H</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX532"><CODE>history-and-alias-expand-line ()</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC115">8.4.8 Some Miscellaneous Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX533"><CODE>history-and-alias-expand-line ()</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC115">8.4.8 Some Miscellaneous Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX526"><CODE>history-expand-line (M-^)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC115">8.4.8 Some Miscellaneous Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX527"><CODE>history-expand-line (M-^)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC115">8.4.8 Some Miscellaneous Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX374"><CODE>history-search-backward ()</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC109">8.4.2 Commands For Manipulating The History</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX375"><CODE>history-search-backward ()</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC109">8.4.2 Commands For Manipulating The History</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX372"><CODE>history-search-forward ()</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC109">8.4.2 Commands For Manipulating The History</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX373"><CODE>history-search-forward ()</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC109">8.4.2 Commands For Manipulating The History</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="fn_I"></A>I</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX508"><CODE>insert-comment (M-#)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC115">8.4.8 Some Miscellaneous Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX509"><CODE>insert-comment (M-#)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC115">8.4.8 Some Miscellaneous Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX444"><CODE>insert-completions (M-*)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC113">8.4.6 Letting Readline Type For You</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX445"><CODE>insert-completions (M-*)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC113">8.4.6 Letting Readline Type For You</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX534"><CODE>insert-last-argument (M-. or M-_)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC115">8.4.8 Some Miscellaneous Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX535"><CODE>insert-last-argument (M-. or M-_)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC115">8.4.8 Some Miscellaneous Commands</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="fn_K"></A>K</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX402"><CODE>kill-line (C-k)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC111">8.4.4 Killing And Yanking</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX403"><CODE>kill-line (C-k)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC111">8.4.4 Killing And Yanking</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX424"><CODE>kill-region ()</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC111">8.4.4 Killing And Yanking</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX425"><CODE>kill-region ()</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC111">8.4.4 Killing And Yanking</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX408"><CODE>kill-whole-line ()</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC111">8.4.4 Killing And Yanking</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX409"><CODE>kill-whole-line ()</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC111">8.4.4 Killing And Yanking</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX410"><CODE>kill-word (M-d)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC111">8.4.4 Killing And Yanking</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX411"><CODE>kill-word (M-d)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC111">8.4.4 Killing And Yanking</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="fn_M"></A>M</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX528"><CODE>magic-space ()</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC115">8.4.8 Some Miscellaneous Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX529"><CODE>magic-space ()</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC115">8.4.8 Some Miscellaneous Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX446"><CODE>menu-complete ()</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC113">8.4.6 Letting Readline Type For You</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX447"><CODE>menu-complete ()</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC113">8.4.6 Letting Readline Type For You</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX448"><CODE>menu-complete-backward ()</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC113">8.4.6 Letting Readline Type For You</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX449"><CODE>menu-complete-backward ()</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC113">8.4.6 Letting Readline Type For You</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="fn_N"></A>N</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX358"><CODE>next-history (C-n)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC109">8.4.2 Commands For Manipulating The History</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX359"><CODE>next-history (C-n)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC109">8.4.2 Commands For Manipulating The History</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX370"><CODE>non-incremental-forward-search-history (M-n)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC109">8.4.2 Commands For Manipulating The History</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX371"><CODE>non-incremental-forward-search-history (M-n)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC109">8.4.2 Commands For Manipulating The History</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX368"><CODE>non-incremental-reverse-search-history (M-p)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC109">8.4.2 Commands For Manipulating The History</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX369"><CODE>non-incremental-reverse-search-history (M-p)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC109">8.4.2 Commands For Manipulating The History</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="fn_O"></A>O</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX536"><CODE>operate-and-get-next (C-o)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC115">8.4.8 Some Miscellaneous Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX537"><CODE>operate-and-get-next (C-o)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC115">8.4.8 Some Miscellaneous Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX400"><CODE>overwrite-mode ()</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC110">8.4.3 Commands For Changing Text</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX401"><CODE>overwrite-mode ()</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC110">8.4.3 Commands For Changing Text</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="fn_P"></A>P</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX470"><CODE>possible-command-completions (C-x !)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC113">8.4.6 Letting Readline Type For You</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX471"><CODE>possible-command-completions (C-x !)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC113">8.4.6 Letting Readline Type For You</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX442"><CODE>possible-completions (M-?)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC113">8.4.6 Letting Readline Type For You</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX443"><CODE>possible-completions (M-?)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC113">8.4.6 Letting Readline Type For You</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX454"><CODE>possible-filename-completions (C-x /)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC113">8.4.6 Letting Readline Type For You</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX455"><CODE>possible-filename-completions (C-x /)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC113">8.4.6 Letting Readline Type For You</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX466"><CODE>possible-hostname-completions (C-x @)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC113">8.4.6 Letting Readline Type For You</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX467"><CODE>possible-hostname-completions (C-x @)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC113">8.4.6 Letting Readline Type For You</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX458"><CODE>possible-username-completions (C-x ~)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC113">8.4.6 Letting Readline Type For You</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX459"><CODE>possible-username-completions (C-x ~)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC113">8.4.6 Letting Readline Type For You</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX462"><CODE>possible-variable-completions (C-x $)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC113">8.4.6 Letting Readline Type For You</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX463"><CODE>possible-variable-completions (C-x $)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC113">8.4.6 Letting Readline Type For You</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX490"><CODE>prefix-meta (<KBD>ESC</KBD>)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC115">8.4.8 Some Miscellaneous Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX491"><CODE>prefix-meta (<KBD>ESC</KBD>)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC115">8.4.8 Some Miscellaneous Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX356"><CODE>previous-history (C-p)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC109">8.4.2 Commands For Manipulating The History</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX357"><CODE>previous-history (C-p)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC109">8.4.2 Commands For Manipulating The History</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="fn_Q"></A>Q</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX386"><CODE>quoted-insert (C-q or C-v)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC110">8.4.3 Commands For Changing Text</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX387"><CODE>quoted-insert (C-q or C-v)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC110">8.4.3 Commands For Changing Text</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="fn_R"></A>R</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX484"><CODE>re-read-init-file (C-x C-r)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC115">8.4.8 Some Miscellaneous Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX485"><CODE>re-read-init-file (C-x C-r)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC115">8.4.8 Some Miscellaneous Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX352"><CODE>redraw-current-line ()</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC108">8.4.1 Commands For Moving</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX353"><CODE>redraw-current-line ()</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC108">8.4.1 Commands For Moving</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX364"><CODE>reverse-search-history (C-r)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC109">8.4.2 Commands For Manipulating The History</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX365"><CODE>reverse-search-history (C-r)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC109">8.4.2 Commands For Manipulating The History</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX494"><CODE>revert-line (M-r)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC115">8.4.8 Some Miscellaneous Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX495"><CODE>revert-line (M-r)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC115">8.4.8 Some Miscellaneous Commands</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="fn_S"></A>S</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX388"><CODE>self-insert (a, b, A, 1, !, <small>...</small>)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC110">8.4.3 Commands For Changing Text</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX389"><CODE>self-insert (a, b, A, 1, !, <small>...</small>)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC110">8.4.3 Commands For Changing Text</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX498"><CODE>set-mark (C-@)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC115">8.4.8 Some Miscellaneous Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX499"><CODE>set-mark (C-@)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC115">8.4.8 Some Miscellaneous Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX348"><CODE>shell-backward-word ()</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC108">8.4.1 Commands For Moving</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX349"><CODE>shell-backward-word ()</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC108">8.4.1 Commands For Moving</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX524"><CODE>shell-expand-line (M-C-e)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC115">8.4.8 Some Miscellaneous Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX525"><CODE>shell-expand-line (M-C-e)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC115">8.4.8 Some Miscellaneous Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX346"><CODE>shell-forward-word ()</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC108">8.4.1 Commands For Moving</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX347"><CODE>shell-forward-word ()</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC108">8.4.1 Commands For Moving</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX414"><CODE>shell-kill-word ()</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC111">8.4.4 Killing And Yanking</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX415"><CODE>shell-kill-word ()</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC111">8.4.4 Killing And Yanking</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX506"><CODE>skip-csi-sequence ()</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC115">8.4.8 Some Miscellaneous Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX507"><CODE>skip-csi-sequence ()</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC115">8.4.8 Some Miscellaneous Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX478"><CODE>start-kbd-macro (C-x ()</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC114">8.4.7 Keyboard Macros</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX479"><CODE>start-kbd-macro (C-x ()</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC114">8.4.7 Keyboard Macros</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="fn_T"></A>T</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX496"><CODE>tilde-expand (M-&#38;)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC115">8.4.8 Some Miscellaneous Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX497"><CODE>tilde-expand (M-&#38;)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC115">8.4.8 Some Miscellaneous Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX390"><CODE>transpose-chars (C-t)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC110">8.4.3 Commands For Changing Text</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX391"><CODE>transpose-chars (C-t)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC110">8.4.3 Commands For Changing Text</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX392"><CODE>transpose-words (M-t)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC110">8.4.3 Commands For Changing Text</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX393"><CODE>transpose-words (M-t)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC110">8.4.3 Commands For Changing Text</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="fn_U"></A>U</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX492"><CODE>undo (C-_ or C-x C-u)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC115">8.4.8 Some Miscellaneous Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX493"><CODE>undo (C-_ or C-x C-u)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC115">8.4.8 Some Miscellaneous Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX438"><CODE>universal-argument ()</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC112">8.4.5 Specifying Numeric Arguments</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX439"><CODE>universal-argument ()</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC112">8.4.5 Specifying Numeric Arguments</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX420"><CODE>unix-filename-rubout ()</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC111">8.4.4 Killing And Yanking</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX421"><CODE>unix-filename-rubout ()</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC111">8.4.4 Killing And Yanking</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX406"><CODE>unix-line-discard (C-u)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC111">8.4.4 Killing And Yanking</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX407"><CODE>unix-line-discard (C-u)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC111">8.4.4 Killing And Yanking</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX418"><CODE>unix-word-rubout (C-w)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC111">8.4.4 Killing And Yanking</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX419"><CODE>unix-word-rubout (C-w)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC111">8.4.4 Killing And Yanking</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX394"><CODE>upcase-word (M-u)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC110">8.4.3 Commands For Changing Text</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX395"><CODE>upcase-word (M-u)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC110">8.4.3 Commands For Changing Text</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="fn_Y"></A>Y</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX432"><CODE>yank (C-y)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC111">8.4.4 Killing And Yanking</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX433"><CODE>yank (C-y)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC111">8.4.4 Killing And Yanking</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX378"><CODE>yank-last-arg (M-. or M-_)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC109">8.4.2 Commands For Manipulating The History</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX379"><CODE>yank-last-arg (M-. or M-_)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC109">8.4.2 Commands For Manipulating The History</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX376"><CODE>yank-nth-arg (M-C-y)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC109">8.4.2 Commands For Manipulating The History</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX377"><CODE>yank-nth-arg (M-C-y)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC109">8.4.2 Commands For Manipulating The History</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX434"><CODE>yank-pop (M-y)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC111">8.4.4 Killing And Yanking</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX435"><CODE>yank-pop (M-y)</CODE></A></TD><TD valign=top><A HREF="bashref.html#SEC111">8.4.4 Killing And Yanking</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +</TABLE><P></P><table><tr><th valign=top>Jump to: </th><td><A HREF="bashref.html#fn_A" style="text-decoration:none"><b>A</b></A> + +<A HREF="bashref.html#fn_B" style="text-decoration:none"><b>B</b></A> + +<A HREF="bashref.html#fn_C" style="text-decoration:none"><b>C</b></A> + +<A HREF="bashref.html#fn_D" style="text-decoration:none"><b>D</b></A> + +<A HREF="bashref.html#fn_E" style="text-decoration:none"><b>E</b></A> + +<A HREF="bashref.html#fn_F" style="text-decoration:none"><b>F</b></A> + +<A 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style="text-decoration:none"><b>Y</b></A> + +</td></tr></table><br><P> + +<A NAME="Concept Index"></A> +<HR SIZE="6"> +<A NAME="SEC145"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC144"> < </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[ > ]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[ << ]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140"> Up </A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[ >> ]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H2> D.5 Concept Index </H2> +<!--docid::SEC145::--> +<table><tr><th valign=top>Jump to: </th><td><A HREF="bashref.html#cp_A" style="text-decoration:none"><b>A</b></A> + +<A HREF="bashref.html#cp_B" style="text-decoration:none"><b>B</b></A> + +<A HREF="bashref.html#cp_C" style="text-decoration:none"><b>C</b></A> + +<A HREF="bashref.html#cp_D" style="text-decoration:none"><b>D</b></A> + +<A HREF="bashref.html#cp_E" style="text-decoration:none"><b>E</b></A> + +<A HREF="bashref.html#cp_F" style="text-decoration:none"><b>F</b></A> + +<A HREF="bashref.html#cp_H" style="text-decoration:none"><b>H</b></A> + +<A HREF="bashref.html#cp_I" style="text-decoration:none"><b>I</b></A> + +<A HREF="bashref.html#cp_J" style="text-decoration:none"><b>J</b></A> + +<A HREF="bashref.html#cp_K" style="text-decoration:none"><b>K</b></A> + +<A HREF="bashref.html#cp_L" style="text-decoration:none"><b>L</b></A> + +<A HREF="bashref.html#cp_M" style="text-decoration:none"><b>M</b></A> + +<A HREF="bashref.html#cp_N" style="text-decoration:none"><b>N</b></A> + +<A HREF="bashref.html#cp_O" style="text-decoration:none"><b>O</b></A> + +<A HREF="bashref.html#cp_P" style="text-decoration:none"><b>P</b></A> + +<A HREF="bashref.html#cp_Q" style="text-decoration:none"><b>Q</b></A> + +<A HREF="bashref.html#cp_R" style="text-decoration:none"><b>R</b></A> + +<A HREF="bashref.html#cp_S" style="text-decoration:none"><b>S</b></A> + +<A HREF="bashref.html#cp_T" style="text-decoration:none"><b>T</b></A> + +<A HREF="bashref.html#cp_V" style="text-decoration:none"><b>V</b></A> + +<A HREF="bashref.html#cp_W" style="text-decoration:none"><b>W</b></A> + +<A HREF="bashref.html#cp_Y" style="text-decoration:none"><b>Y</b></A> + +</td></tr></table><br><P></P> +<TABLE border=0> +<TR><TD></TD><TH ALIGN=LEFT>Index Entry</TH><TH ALIGN=LEFT> Section</TH></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="cp_A"></A>A</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC84">alias expansion</A></TD><TD valign=top><A HREF="bashref.html#SEC84">6.6 Aliases</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC83">arithmetic evaluation</A></TD><TD valign=top><A HREF="bashref.html#SEC83">6.5 Shell Arithmetic</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC33">arithmetic expansion</A></TD><TD valign=top><A HREF="bashref.html#SEC33">3.5.5 Arithmetic Expansion</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC83">arithmetic, shell</A></TD><TD valign=top><A HREF="bashref.html#SEC83">6.5 Shell Arithmetic</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC85">arrays</A></TD><TD valign=top><A HREF="bashref.html#SEC85">6.7 Arrays</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="cp_B"></A>B</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC92">background</A></TD><TD valign=top><A HREF="bashref.html#SEC92">7.1 Job Control Basics</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC127">Bash configuration</A></TD><TD valign=top><A HREF="bashref.html#SEC127">10.1 Basic Installation</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC127">Bash installation</A></TD><TD valign=top><A HREF="bashref.html#SEC127">10.1 Basic Installation</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC5">Bourne shell</A></TD><TD valign=top><A HREF="bashref.html#SEC5">3. Basic Shell Features</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC29">brace expansion</A></TD><TD valign=top><A HREF="bashref.html#SEC29">3.5.1 Brace Expansion</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX2">builtin</A></TD><TD valign=top><A HREF="bashref.html#SEC4">2. Definitions</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="cp_C"></A>C</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC98">command editing</A></TD><TD valign=top><A HREF="bashref.html#SEC98">8.2.1 Readline Bare Essentials</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC52">command execution</A></TD><TD valign=top><A HREF="bashref.html#SEC52">3.7.2 Command Search and Execution</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC51">command expansion</A></TD><TD valign=top><A HREF="bashref.html#SEC51">3.7.1 Simple Command Expansion</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC120">command history</A></TD><TD valign=top><A HREF="bashref.html#SEC120">9.1 Bash History Facilities</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC52">command search</A></TD><TD valign=top><A HREF="bashref.html#SEC52">3.7.2 Command Search and Execution</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC32">command substitution</A></TD><TD valign=top><A HREF="bashref.html#SEC32">3.5.4 Command Substitution</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX26">command timing</A></TD><TD valign=top><A HREF="bashref.html#SEC17">3.2.2 Pipelines</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC19">commands, compound</A></TD><TD valign=top><A HREF="bashref.html#SEC19">3.2.4 Compound Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC21">commands, conditional</A></TD><TD valign=top><A HREF="bashref.html#SEC21">3.2.4.2 Conditional Constructs</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC22">commands, grouping</A></TD><TD valign=top><A HREF="bashref.html#SEC22">3.2.4.3 Grouping Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC18">commands, lists</A></TD><TD valign=top><A HREF="bashref.html#SEC18">3.2.3 Lists of Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC20">commands, looping</A></TD><TD valign=top><A HREF="bashref.html#SEC20">3.2.4.1 Looping Constructs</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC17">commands, pipelines</A></TD><TD valign=top><A HREF="bashref.html#SEC17">3.2.2 Pipelines</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC15">commands, shell</A></TD><TD valign=top><A HREF="bashref.html#SEC15">3.2 Shell Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC16">commands, simple</A></TD><TD valign=top><A HREF="bashref.html#SEC16">3.2.1 Simple Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC14">comments, shell</A></TD><TD valign=top><A HREF="bashref.html#SEC14">3.1.3 Comments</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC118">completion builtins</A></TD><TD valign=top><A HREF="bashref.html#SEC118">8.7 Programmable Completion Builtins</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC127">configuration</A></TD><TD valign=top><A HREF="bashref.html#SEC127">10.1 Basic Installation</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX3">control operator</A></TD><TD valign=top><A HREF="bashref.html#SEC4">2. Definitions</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC23">coprocess</A></TD><TD valign=top><A HREF="bashref.html#SEC23">3.2.5 Coprocesses</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="cp_D"></A>D</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC86">directory stack</A></TD><TD valign=top><A HREF="bashref.html#SEC86">6.8 The Directory Stack</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="cp_E"></A>E</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC98">editing command lines</A></TD><TD valign=top><A HREF="bashref.html#SEC98">8.2.1 Readline Bare Essentials</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC54">environment</A></TD><TD valign=top><A HREF="bashref.html#SEC54">3.7.4 Environment</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC83">evaluation, arithmetic</A></TD><TD valign=top><A HREF="bashref.html#SEC83">6.5 Shell Arithmetic</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC123">event designators</A></TD><TD valign=top><A HREF="bashref.html#SEC123">9.3.1 Event Designators</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC53">execution environment</A></TD><TD valign=top><A HREF="bashref.html#SEC53">3.7.3 Command Execution Environment</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX4">exit status</A></TD><TD valign=top><A HREF="bashref.html#SEC4">2. Definitions</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC55">exit status</A></TD><TD valign=top><A HREF="bashref.html#SEC55">3.7.5 Exit Status</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC28">expansion</A></TD><TD valign=top><A HREF="bashref.html#SEC28">3.5 Shell Expansions</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC33">expansion, arithmetic</A></TD><TD valign=top><A HREF="bashref.html#SEC33">3.5.5 Arithmetic Expansion</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC29">expansion, brace</A></TD><TD valign=top><A HREF="bashref.html#SEC29">3.5.1 Brace Expansion</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX64">expansion, filename</A></TD><TD valign=top><A HREF="bashref.html#SEC36">3.5.8 Filename Expansion</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC31">expansion, parameter</A></TD><TD valign=top><A HREF="bashref.html#SEC31">3.5.3 Shell Parameter Expansion</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX65">expansion, pathname</A></TD><TD valign=top><A HREF="bashref.html#SEC36">3.5.8 Filename Expansion</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC30">expansion, tilde</A></TD><TD valign=top><A HREF="bashref.html#SEC30">3.5.2 Tilde Expansion</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC83">expressions, arithmetic</A></TD><TD valign=top><A HREF="bashref.html#SEC83">6.5 Shell Arithmetic</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC82">expressions, conditional</A></TD><TD valign=top><A HREF="bashref.html#SEC82">6.4 Bash Conditional Expressions</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="cp_F"></A>F</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX5">field</A></TD><TD valign=top><A HREF="bashref.html#SEC4">2. Definitions</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX6">filename</A></TD><TD valign=top><A HREF="bashref.html#SEC4">2. Definitions</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX66">filename expansion</A></TD><TD valign=top><A HREF="bashref.html#SEC36">3.5.8 Filename Expansion</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC92">foreground</A></TD><TD valign=top><A HREF="bashref.html#SEC92">7.1 Job Control Basics</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC24">functions, shell</A></TD><TD valign=top><A HREF="bashref.html#SEC24">3.3 Shell Functions</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="cp_H"></A>H</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC121">history builtins</A></TD><TD valign=top><A HREF="bashref.html#SEC121">9.2 Bash History Builtins</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX546">history events</A></TD><TD valign=top><A HREF="bashref.html#SEC123">9.3.1 Event Designators</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC122">history expansion</A></TD><TD valign=top><A HREF="bashref.html#SEC122">9.3 History Expansion</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC120">history list</A></TD><TD valign=top><A HREF="bashref.html#SEC120">9.1 Bash History Facilities</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX543">History, how to use</A></TD><TD valign=top><A HREF="bashref.html#SEC118">8.7 Programmable Completion Builtins</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="cp_I"></A>I</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX11">identifier</A></TD><TD valign=top><A HREF="bashref.html#SEC4">2. Definitions</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC103">initialization file, readline</A></TD><TD valign=top><A HREF="bashref.html#SEC103">8.3 Readline Init File</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC127">installation</A></TD><TD valign=top><A HREF="bashref.html#SEC127">10.1 Basic Installation</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC97">interaction, readline</A></TD><TD valign=top><A HREF="bashref.html#SEC97">8.2 Readline Interaction</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX289">interactive shell</A></TD><TD valign=top><A HREF="bashref.html#SEC69">6.1 Invoking Bash</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC78">interactive shell</A></TD><TD valign=top><A HREF="bashref.html#SEC78">6.3 Interactive Shells</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC13">internationalization</A></TD><TD valign=top><A HREF="bashref.html#SEC13">3.1.2.5 Locale-Specific Translation</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="cp_J"></A>J</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX7">job</A></TD><TD valign=top><A HREF="bashref.html#SEC4">2. Definitions</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX8">job control</A></TD><TD valign=top><A HREF="bashref.html#SEC4">2. Definitions</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC92">job control</A></TD><TD valign=top><A HREF="bashref.html#SEC92">7.1 Job Control Basics</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="cp_K"></A>K</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX305">kill ring</A></TD><TD valign=top><A HREF="bashref.html#SEC100">8.2.3 Readline Killing Commands</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX303">killing text</A></TD><TD valign=top><A HREF="bashref.html#SEC100">8.2.3 Readline Killing Commands</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="cp_L"></A>L</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC13">localization</A></TD><TD valign=top><A HREF="bashref.html#SEC13">3.1.2.5 Locale-Specific Translation</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX288">login shell</A></TD><TD valign=top><A HREF="bashref.html#SEC69">6.1 Invoking Bash</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="cp_M"></A>M</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC37">matching, pattern</A></TD><TD valign=top><A HREF="bashref.html#SEC37">3.5.8.1 Pattern Matching</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX9">metacharacter</A></TD><TD valign=top><A HREF="bashref.html#SEC4">2. Definitions</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="cp_N"></A>N</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX10">name</A></TD><TD valign=top><A HREF="bashref.html#SEC4">2. Definitions</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC13">native languages</A></TD><TD valign=top><A HREF="bashref.html#SEC13">3.1.2.5 Locale-Specific Translation</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC98">notation, readline</A></TD><TD valign=top><A HREF="bashref.html#SEC98">8.2.1 Readline Bare Essentials</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="cp_O"></A>O</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX12">operator, shell</A></TD><TD valign=top><A HREF="bashref.html#SEC4">2. Definitions</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="cp_P"></A>P</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC31">parameter expansion</A></TD><TD valign=top><A HREF="bashref.html#SEC31">3.5.3 Shell Parameter Expansion</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC25">parameters</A></TD><TD valign=top><A HREF="bashref.html#SEC25">3.4 Shell Parameters</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC26">parameters, positional</A></TD><TD valign=top><A HREF="bashref.html#SEC26">3.4.1 Positional Parameters</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC27">parameters, special</A></TD><TD valign=top><A HREF="bashref.html#SEC27">3.4.2 Special Parameters</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX67">pathname expansion</A></TD><TD valign=top><A HREF="bashref.html#SEC36">3.5.8 Filename Expansion</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC37">pattern matching</A></TD><TD valign=top><A HREF="bashref.html#SEC37">3.5.8.1 Pattern Matching</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC17">pipeline</A></TD><TD valign=top><A HREF="bashref.html#SEC17">3.2.2 Pipelines</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX1">POSIX</A></TD><TD valign=top><A HREF="bashref.html#SEC4">2. Definitions</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC90">POSIX Mode</A></TD><TD valign=top><A HREF="bashref.html#SEC90">6.11 Bash POSIX Mode</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX13">process group</A></TD><TD valign=top><A HREF="bashref.html#SEC4">2. Definitions</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX14">process group ID</A></TD><TD valign=top><A HREF="bashref.html#SEC4">2. Definitions</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC34">process substitution</A></TD><TD valign=top><A HREF="bashref.html#SEC34">3.5.6 Process Substitution</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC117">programmable completion</A></TD><TD valign=top><A HREF="bashref.html#SEC117">8.6 Programmable Completion</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC88">prompting</A></TD><TD valign=top><A HREF="bashref.html#SEC88">6.9 Controlling the Prompt</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="cp_Q"></A>Q</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC8">quoting</A></TD><TD valign=top><A HREF="bashref.html#SEC8">3.1.2 Quoting</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC12">quoting, ANSI</A></TD><TD valign=top><A HREF="bashref.html#SEC12">3.1.2.4 ANSI-C Quoting</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="cp_R"></A>R</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX302">Readline, how to use</A></TD><TD valign=top><A HREF="bashref.html#SEC94">7.3 Job Control Variables</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC39">redirection</A></TD><TD valign=top><A HREF="bashref.html#SEC39">3.6 Redirections</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX15">reserved word</A></TD><TD valign=top><A HREF="bashref.html#SEC4">2. Definitions</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC89">restricted shell</A></TD><TD valign=top><A HREF="bashref.html#SEC89">6.10 The Restricted Shell</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX16">return status</A></TD><TD valign=top><A HREF="bashref.html#SEC4">2. Definitions</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="cp_S"></A>S</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC83">shell arithmetic</A></TD><TD valign=top><A HREF="bashref.html#SEC83">6.5 Shell Arithmetic</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC24">shell function</A></TD><TD valign=top><A HREF="bashref.html#SEC24">3.3 Shell Functions</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC57">shell script</A></TD><TD valign=top><A HREF="bashref.html#SEC57">3.8 Shell Scripts</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC25">shell variable</A></TD><TD valign=top><A HREF="bashref.html#SEC25">3.4 Shell Parameters</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC78">shell, interactive</A></TD><TD valign=top><A HREF="bashref.html#SEC78">6.3 Interactive Shells</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX17">signal</A></TD><TD valign=top><A HREF="bashref.html#SEC4">2. Definitions</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC56">signal handling</A></TD><TD valign=top><A HREF="bashref.html#SEC56">3.7.6 Signals</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX18">special builtin</A></TD><TD valign=top><A HREF="bashref.html#SEC4">2. Definitions</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC64">special builtin</A></TD><TD valign=top><A HREF="bashref.html#SEC64">4.4 Special Builtins</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC70">startup files</A></TD><TD valign=top><A HREF="bashref.html#SEC70">6.2 Bash Startup Files</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC92">suspending jobs</A></TD><TD valign=top><A HREF="bashref.html#SEC92">7.1 Job Control Basics</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="cp_T"></A>T</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC30">tilde expansion</A></TD><TD valign=top><A HREF="bashref.html#SEC30">3.5.2 Tilde Expansion</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX19">token</A></TD><TD valign=top><A HREF="bashref.html#SEC4">2. Definitions</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC13">translation, native languages</A></TD><TD valign=top><A HREF="bashref.html#SEC13">3.1.2.5 Locale-Specific Translation</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="cp_V"></A>V</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC25">variable, shell</A></TD><TD valign=top><A HREF="bashref.html#SEC25">3.4 Shell Parameters</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX306">variables, readline</A></TD><TD valign=top><A HREF="bashref.html#SEC104">8.3.1 Readline Init File Syntax</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="cp_W"></A>W</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX20">word</A></TD><TD valign=top><A HREF="bashref.html#SEC4">2. Definitions</A></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#SEC35">word splitting</A></TD><TD valign=top><A HREF="bashref.html#SEC35">3.5.7 Word Splitting</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +<TR><TH><A NAME="cp_Y"></A>Y</TH><TD></TD><TD></TD></TR> +<TR><TD></TD><TD valign=top><A HREF="bashref.html#IDX304">yanking text</A></TD><TD valign=top><A HREF="bashref.html#SEC100">8.2.3 Readline Killing Commands</A></TD></TR> +<TR><TD COLSPAN=3> <HR></TD></TR> +</TABLE><P></P><table><tr><th valign=top>Jump to: </th><td><A HREF="bashref.html#cp_A" style="text-decoration:none"><b>A</b></A> + +<A HREF="bashref.html#cp_B" style="text-decoration:none"><b>B</b></A> + +<A HREF="bashref.html#cp_C" style="text-decoration:none"><b>C</b></A> + +<A HREF="bashref.html#cp_D" style="text-decoration:none"><b>D</b></A> + +<A HREF="bashref.html#cp_E" style="text-decoration:none"><b>E</b></A> + +<A HREF="bashref.html#cp_F" style="text-decoration:none"><b>F</b></A> + +<A HREF="bashref.html#cp_H" style="text-decoration:none"><b>H</b></A> + +<A HREF="bashref.html#cp_I" style="text-decoration:none"><b>I</b></A> + +<A HREF="bashref.html#cp_J" style="text-decoration:none"><b>J</b></A> + +<A HREF="bashref.html#cp_K" style="text-decoration:none"><b>K</b></A> + +<A HREF="bashref.html#cp_L" style="text-decoration:none"><b>L</b></A> + +<A HREF="bashref.html#cp_M" style="text-decoration:none"><b>M</b></A> + +<A HREF="bashref.html#cp_N" style="text-decoration:none"><b>N</b></A> + +<A HREF="bashref.html#cp_O" style="text-decoration:none"><b>O</b></A> + +<A HREF="bashref.html#cp_P" style="text-decoration:none"><b>P</b></A> + +<A HREF="bashref.html#cp_Q" style="text-decoration:none"><b>Q</b></A> + +<A HREF="bashref.html#cp_R" style="text-decoration:none"><b>R</b></A> + +<A HREF="bashref.html#cp_S" style="text-decoration:none"><b>S</b></A> + +<A HREF="bashref.html#cp_T" style="text-decoration:none"><b>T</b></A> + +<A HREF="bashref.html#cp_V" style="text-decoration:none"><b>V</b></A> + +<A HREF="bashref.html#cp_W" style="text-decoration:none"><b>W</b></A> + +<A HREF="bashref.html#cp_Y" style="text-decoration:none"><b>Y</b></A> + +</td></tr></table><br><P> + +<HR SIZE="6"> +<A NAME="SEC_Contents"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H1>Table of Contents</H1> +<UL> +<A NAME="TOC1" HREF="bashref.html#SEC1">1. Introduction</A> +<BR> +<UL> +<A NAME="TOC2" HREF="bashref.html#SEC2">1.1 What is Bash?</A> +<BR> +<A NAME="TOC3" HREF="bashref.html#SEC3">1.2 What is a shell?</A> +<BR> +</UL> +<A NAME="TOC4" HREF="bashref.html#SEC4">2. Definitions</A> +<BR> +<A NAME="TOC5" HREF="bashref.html#SEC5">3. Basic Shell Features</A> +<BR> +<UL> +<A NAME="TOC6" HREF="bashref.html#SEC6">3.1 Shell Syntax</A> +<BR> +<UL> +<A NAME="TOC7" HREF="bashref.html#SEC7">3.1.1 Shell Operation</A> +<BR> +<A NAME="TOC8" HREF="bashref.html#SEC8">3.1.2 Quoting</A> +<BR> +<UL> +<A NAME="TOC9" HREF="bashref.html#SEC9">3.1.2.1 Escape Character</A> +<BR> +<A NAME="TOC10" HREF="bashref.html#SEC10">3.1.2.2 Single Quotes</A> +<BR> +<A NAME="TOC11" HREF="bashref.html#SEC11">3.1.2.3 Double Quotes</A> +<BR> +<A NAME="TOC12" HREF="bashref.html#SEC12">3.1.2.4 ANSI-C Quoting</A> +<BR> +<A NAME="TOC13" HREF="bashref.html#SEC13">3.1.2.5 Locale-Specific Translation</A> +<BR> +</UL> +<A NAME="TOC14" HREF="bashref.html#SEC14">3.1.3 Comments</A> +<BR> +</UL> +<A NAME="TOC15" HREF="bashref.html#SEC15">3.2 Shell Commands</A> +<BR> +<UL> +<A NAME="TOC16" HREF="bashref.html#SEC16">3.2.1 Simple Commands</A> +<BR> +<A NAME="TOC17" HREF="bashref.html#SEC17">3.2.2 Pipelines</A> +<BR> +<A NAME="TOC18" HREF="bashref.html#SEC18">3.2.3 Lists of Commands</A> +<BR> +<A NAME="TOC19" HREF="bashref.html#SEC19">3.2.4 Compound Commands</A> +<BR> +<UL> +<A NAME="TOC20" HREF="bashref.html#SEC20">3.2.4.1 Looping Constructs</A> +<BR> +<A NAME="TOC21" HREF="bashref.html#SEC21">3.2.4.2 Conditional Constructs</A> +<BR> +<A NAME="TOC22" HREF="bashref.html#SEC22">3.2.4.3 Grouping Commands</A> +<BR> +</UL> +<A NAME="TOC23" HREF="bashref.html#SEC23">3.2.5 Coprocesses</A> +<BR> +</UL> +<A NAME="TOC24" HREF="bashref.html#SEC24">3.3 Shell Functions</A> +<BR> +<A NAME="TOC25" HREF="bashref.html#SEC25">3.4 Shell Parameters</A> +<BR> +<UL> +<A NAME="TOC26" HREF="bashref.html#SEC26">3.4.1 Positional Parameters</A> +<BR> +<A NAME="TOC27" HREF="bashref.html#SEC27">3.4.2 Special Parameters</A> +<BR> +</UL> +<A NAME="TOC28" HREF="bashref.html#SEC28">3.5 Shell Expansions</A> +<BR> +<UL> +<A NAME="TOC29" HREF="bashref.html#SEC29">3.5.1 Brace Expansion</A> +<BR> +<A NAME="TOC30" HREF="bashref.html#SEC30">3.5.2 Tilde Expansion</A> +<BR> +<A NAME="TOC31" HREF="bashref.html#SEC31">3.5.3 Shell Parameter Expansion</A> +<BR> +<A NAME="TOC32" HREF="bashref.html#SEC32">3.5.4 Command Substitution</A> +<BR> +<A NAME="TOC33" HREF="bashref.html#SEC33">3.5.5 Arithmetic Expansion</A> +<BR> +<A NAME="TOC34" HREF="bashref.html#SEC34">3.5.6 Process Substitution</A> +<BR> +<A NAME="TOC35" HREF="bashref.html#SEC35">3.5.7 Word Splitting</A> +<BR> +<A NAME="TOC36" HREF="bashref.html#SEC36">3.5.8 Filename Expansion</A> +<BR> +<UL> +<A NAME="TOC37" HREF="bashref.html#SEC37">3.5.8.1 Pattern Matching</A> +<BR> +</UL> +<A NAME="TOC38" HREF="bashref.html#SEC38">3.5.9 Quote Removal</A> +<BR> +</UL> +<A NAME="TOC39" HREF="bashref.html#SEC39">3.6 Redirections</A> +<BR> +<UL> +<A NAME="TOC40" HREF="bashref.html#SEC40">3.6.1 Redirecting Input</A> +<BR> +<A NAME="TOC41" HREF="bashref.html#SEC41">3.6.2 Redirecting Output</A> +<BR> +<A NAME="TOC42" HREF="bashref.html#SEC42">3.6.3 Appending Redirected Output</A> +<BR> +<A NAME="TOC43" HREF="bashref.html#SEC43">3.6.4 Redirecting Standard Output and Standard Error</A> +<BR> +<A NAME="TOC44" HREF="bashref.html#SEC44">3.6.5 Appending Standard Output and Standard Error</A> +<BR> +<A NAME="TOC45" HREF="bashref.html#SEC45">3.6.6 Here Documents</A> +<BR> +<A NAME="TOC46" HREF="bashref.html#SEC46">3.6.7 Here Strings</A> +<BR> +<A NAME="TOC47" HREF="bashref.html#SEC47">3.6.8 Duplicating File Descriptors</A> +<BR> +<A NAME="TOC48" HREF="bashref.html#SEC48">3.6.9 Moving File Descriptors</A> +<BR> +<A NAME="TOC49" HREF="bashref.html#SEC49">3.6.10 Opening File Descriptors for Reading and Writing</A> +<BR> +</UL> +<A NAME="TOC50" HREF="bashref.html#SEC50">3.7 Executing Commands</A> +<BR> +<UL> +<A NAME="TOC51" HREF="bashref.html#SEC51">3.7.1 Simple Command Expansion</A> +<BR> +<A NAME="TOC52" HREF="bashref.html#SEC52">3.7.2 Command Search and Execution</A> +<BR> +<A NAME="TOC53" HREF="bashref.html#SEC53">3.7.3 Command Execution Environment</A> +<BR> +<A NAME="TOC54" HREF="bashref.html#SEC54">3.7.4 Environment</A> +<BR> +<A NAME="TOC55" HREF="bashref.html#SEC55">3.7.5 Exit Status</A> +<BR> +<A NAME="TOC56" HREF="bashref.html#SEC56">3.7.6 Signals</A> +<BR> +</UL> +<A NAME="TOC57" HREF="bashref.html#SEC57">3.8 Shell Scripts</A> +<BR> +</UL> +<A NAME="TOC58" HREF="bashref.html#SEC58">4. Shell Builtin Commands</A> +<BR> +<UL> +<A NAME="TOC59" HREF="bashref.html#SEC59">4.1 Bourne Shell Builtins</A> +<BR> +<A NAME="TOC60" HREF="bashref.html#SEC60">4.2 Bash Builtin Commands</A> +<BR> +<A NAME="TOC61" HREF="bashref.html#SEC61">4.3 Modifying Shell Behavior</A> +<BR> +<UL> +<A NAME="TOC62" HREF="bashref.html#SEC62">4.3.1 The Set Builtin</A> +<BR> +<A NAME="TOC63" HREF="bashref.html#SEC63">4.3.2 The Shopt Builtin</A> +<BR> +</UL> +<A NAME="TOC64" HREF="bashref.html#SEC64">4.4 Special Builtins</A> +<BR> +</UL> +<A NAME="TOC65" HREF="bashref.html#SEC65">5. Shell Variables</A> +<BR> +<UL> +<A NAME="TOC66" HREF="bashref.html#SEC66">5.1 Bourne Shell Variables</A> +<BR> +<A NAME="TOC67" HREF="bashref.html#SEC67">5.2 Bash Variables</A> +<BR> +</UL> +<A NAME="TOC68" HREF="bashref.html#SEC68">6. Bash Features</A> +<BR> +<UL> +<A NAME="TOC69" HREF="bashref.html#SEC69">6.1 Invoking Bash</A> +<BR> +<A NAME="TOC70" HREF="bashref.html#SEC70">6.2 Bash Startup Files</A> +<BR> +<A NAME="TOC78" HREF="bashref.html#SEC78">6.3 Interactive Shells</A> +<BR> +<UL> +<A NAME="TOC79" HREF="bashref.html#SEC79">6.3.1 What is an Interactive Shell?</A> +<BR> +<A NAME="TOC80" HREF="bashref.html#SEC80">6.3.2 Is this Shell Interactive?</A> +<BR> +<A NAME="TOC81" HREF="bashref.html#SEC81">6.3.3 Interactive Shell Behavior</A> +<BR> +</UL> +<A NAME="TOC82" HREF="bashref.html#SEC82">6.4 Bash Conditional Expressions</A> +<BR> +<A NAME="TOC83" HREF="bashref.html#SEC83">6.5 Shell Arithmetic</A> +<BR> +<A NAME="TOC84" HREF="bashref.html#SEC84">6.6 Aliases</A> +<BR> +<A NAME="TOC85" HREF="bashref.html#SEC85">6.7 Arrays</A> +<BR> +<A NAME="TOC86" HREF="bashref.html#SEC86">6.8 The Directory Stack</A> +<BR> +<UL> +<A NAME="TOC87" HREF="bashref.html#SEC87">6.8.1 Directory Stack Builtins</A> +<BR> +</UL> +<A NAME="TOC88" HREF="bashref.html#SEC88">6.9 Controlling the Prompt</A> +<BR> +<A NAME="TOC89" HREF="bashref.html#SEC89">6.10 The Restricted Shell</A> +<BR> +<A NAME="TOC90" HREF="bashref.html#SEC90">6.11 Bash POSIX Mode</A> +<BR> +</UL> +<A NAME="TOC91" HREF="bashref.html#SEC91">7. Job Control</A> +<BR> +<UL> +<A NAME="TOC92" HREF="bashref.html#SEC92">7.1 Job Control Basics</A> +<BR> +<A NAME="TOC93" HREF="bashref.html#SEC93">7.2 Job Control Builtins</A> +<BR> +<A NAME="TOC94" HREF="bashref.html#SEC94">7.3 Job Control Variables</A> +<BR> +</UL> +<A NAME="TOC95" HREF="bashref.html#SEC95">8. Command Line Editing</A> +<BR> +<UL> +<A NAME="TOC96" HREF="bashref.html#SEC96">8.1 Introduction to Line Editing</A> +<BR> +<A NAME="TOC97" HREF="bashref.html#SEC97">8.2 Readline Interaction</A> +<BR> +<UL> +<A NAME="TOC98" HREF="bashref.html#SEC98">8.2.1 Readline Bare Essentials</A> +<BR> +<A NAME="TOC99" HREF="bashref.html#SEC99">8.2.2 Readline Movement Commands</A> +<BR> +<A NAME="TOC100" HREF="bashref.html#SEC100">8.2.3 Readline Killing Commands</A> +<BR> +<A NAME="TOC101" HREF="bashref.html#SEC101">8.2.4 Readline Arguments</A> +<BR> +<A NAME="TOC102" HREF="bashref.html#SEC102">8.2.5 Searching for Commands in the History</A> +<BR> +</UL> +<A NAME="TOC103" HREF="bashref.html#SEC103">8.3 Readline Init File</A> +<BR> +<UL> +<A NAME="TOC104" HREF="bashref.html#SEC104">8.3.1 Readline Init File Syntax</A> +<BR> +<A NAME="TOC105" HREF="bashref.html#SEC105">8.3.2 Conditional Init Constructs</A> +<BR> +<A NAME="TOC106" HREF="bashref.html#SEC106">8.3.3 Sample Init File</A> +<BR> +</UL> +<A NAME="TOC107" HREF="bashref.html#SEC107">8.4 Bindable Readline Commands</A> +<BR> +<UL> +<A NAME="TOC108" HREF="bashref.html#SEC108">8.4.1 Commands For Moving</A> +<BR> +<A NAME="TOC109" HREF="bashref.html#SEC109">8.4.2 Commands For Manipulating The History</A> +<BR> +<A NAME="TOC110" HREF="bashref.html#SEC110">8.4.3 Commands For Changing Text</A> +<BR> +<A NAME="TOC111" HREF="bashref.html#SEC111">8.4.4 Killing And Yanking</A> +<BR> +<A NAME="TOC112" HREF="bashref.html#SEC112">8.4.5 Specifying Numeric Arguments</A> +<BR> +<A NAME="TOC113" HREF="bashref.html#SEC113">8.4.6 Letting Readline Type For You</A> +<BR> +<A NAME="TOC114" HREF="bashref.html#SEC114">8.4.7 Keyboard Macros</A> +<BR> +<A NAME="TOC115" HREF="bashref.html#SEC115">8.4.8 Some Miscellaneous Commands</A> +<BR> +</UL> +<A NAME="TOC116" HREF="bashref.html#SEC116">8.5 Readline vi Mode</A> +<BR> +<A NAME="TOC117" HREF="bashref.html#SEC117">8.6 Programmable Completion</A> +<BR> +<A NAME="TOC118" HREF="bashref.html#SEC118">8.7 Programmable Completion Builtins</A> +<BR> +</UL> +<A NAME="TOC119" HREF="bashref.html#SEC119">9. Using History Interactively</A> +<BR> +<UL> +<A NAME="TOC120" HREF="bashref.html#SEC120">9.1 Bash History Facilities</A> +<BR> +<A NAME="TOC121" HREF="bashref.html#SEC121">9.2 Bash History Builtins</A> +<BR> +<A NAME="TOC122" HREF="bashref.html#SEC122">9.3 History Expansion</A> +<BR> +<UL> +<A NAME="TOC123" HREF="bashref.html#SEC123">9.3.1 Event Designators</A> +<BR> +<A NAME="TOC124" HREF="bashref.html#SEC124">9.3.2 Word Designators</A> +<BR> +<A NAME="TOC125" HREF="bashref.html#SEC125">9.3.3 Modifiers</A> +<BR> +</UL> +</UL> +<A NAME="TOC126" HREF="bashref.html#SEC126">10. Installing Bash</A> +<BR> +<UL> +<A NAME="TOC127" HREF="bashref.html#SEC127">10.1 Basic Installation</A> +<BR> +<A NAME="TOC128" HREF="bashref.html#SEC128">10.2 Compilers and Options</A> +<BR> +<A NAME="TOC129" HREF="bashref.html#SEC129">10.3 Compiling For Multiple Architectures</A> +<BR> +<A NAME="TOC130" HREF="bashref.html#SEC130">10.4 Installation Names</A> +<BR> +<A NAME="TOC131" HREF="bashref.html#SEC131">10.5 Specifying the System Type</A> +<BR> +<A NAME="TOC132" HREF="bashref.html#SEC132">10.6 Sharing Defaults</A> +<BR> +<A NAME="TOC133" HREF="bashref.html#SEC133">10.7 Operation Controls</A> +<BR> +<A NAME="TOC134" HREF="bashref.html#SEC134">10.8 Optional Features</A> +<BR> +</UL> +<A NAME="TOC135" HREF="bashref.html#SEC135">A. Reporting Bugs</A> +<BR> +<A NAME="TOC136" HREF="bashref.html#SEC136">B. Major Differences From The Bourne Shell</A> +<BR> +<UL> +<A NAME="TOC137" HREF="bashref.html#SEC137">B.1 Implementation Differences From The SVR4.2 Shell</A> +<BR> +</UL> +<A NAME="TOC138" HREF="bashref.html#SEC138">C. GNU Free Documentation License</A> +<BR> +<A NAME="TOC140" HREF="bashref.html#SEC140">D. Indexes</A> +<BR> +<UL> +<A NAME="TOC141" HREF="bashref.html#SEC141">D.1 Index of Shell Builtin Commands</A> +<BR> +<A NAME="TOC142" HREF="bashref.html#SEC142">D.2 Index of Shell Reserved Words</A> +<BR> +<A NAME="TOC143" HREF="bashref.html#SEC143">D.3 Parameter and Variable Index</A> +<BR> +<A NAME="TOC144" HREF="bashref.html#SEC144">D.4 Function Index</A> +<BR> +<A NAME="TOC145" HREF="bashref.html#SEC145">D.5 Concept Index</A> +<BR> +</UL> +</UL> +<HR SIZE=1> +<A NAME="SEC_OVERVIEW"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H1>Short Table of Contents</H1> +<BLOCKQUOTE> +<A NAME="TOC1" HREF="bashref.html#SEC1">1. Introduction</A> +<BR> +<A NAME="TOC4" HREF="bashref.html#SEC4">2. Definitions</A> +<BR> +<A NAME="TOC5" HREF="bashref.html#SEC5">3. Basic Shell Features</A> +<BR> +<A NAME="TOC58" HREF="bashref.html#SEC58">4. Shell Builtin Commands</A> +<BR> +<A NAME="TOC65" HREF="bashref.html#SEC65">5. Shell Variables</A> +<BR> +<A NAME="TOC68" HREF="bashref.html#SEC68">6. Bash Features</A> +<BR> +<A NAME="TOC91" HREF="bashref.html#SEC91">7. Job Control</A> +<BR> +<A NAME="TOC95" HREF="bashref.html#SEC95">8. Command Line Editing</A> +<BR> +<A NAME="TOC119" HREF="bashref.html#SEC119">9. Using History Interactively</A> +<BR> +<A NAME="TOC126" HREF="bashref.html#SEC126">10. Installing Bash</A> +<BR> +<A NAME="TOC135" HREF="bashref.html#SEC135">A. Reporting Bugs</A> +<BR> +<A NAME="TOC136" HREF="bashref.html#SEC136">B. Major Differences From The Bourne Shell</A> +<BR> +<A NAME="TOC138" HREF="bashref.html#SEC138">C. GNU Free Documentation License</A> +<BR> +<A NAME="TOC140" HREF="bashref.html#SEC140">D. Indexes</A> +<BR> + +</BLOCKQUOTE> +<HR SIZE=1> +<A NAME="SEC_About"></A> +<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> +<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Top">Top</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_Contents">Contents</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC140">Index</A>]</TD> +<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="bashref.html#SEC_About"> ? </A>]</TD> +</TR></TABLE> +<H1>About this document</H1> +This document was generated by <I>Chet Ramey</I> on <I>December, 29 2009</I> +using <A HREF="http://www.mathematik.uni-kl.de/~obachman/Texi2html +"><I>texi2html</I></A> +<P></P> +The buttons in the navigation panels have the following meaning: +<P></P> +<table border = "1"> +<TR> +<TH> Button </TH> +<TH> Name </TH> +<TH> Go to </TH> +<TH> From 1.2.3 go to</TH> +</TR> +<TR> +<TD ALIGN="CENTER"> + [ < ] </TD> +<TD ALIGN="CENTER"> +Back +</TD> +<TD> +previous section in reading order +</TD> +<TD> +1.2.2 +</TD> +</TR> +<TR> +<TD ALIGN="CENTER"> + [ > ] </TD> +<TD ALIGN="CENTER"> +Forward +</TD> +<TD> +next section in reading order +</TD> +<TD> +1.2.4 +</TD> +</TR> +<TR> +<TD ALIGN="CENTER"> + [ << ] </TD> +<TD ALIGN="CENTER"> +FastBack +</TD> +<TD> +previous or up-and-previous section +</TD> +<TD> +1.1 +</TD> +</TR> +<TR> +<TD ALIGN="CENTER"> + [ Up ] </TD> +<TD ALIGN="CENTER"> +Up +</TD> +<TD> +up section +</TD> +<TD> +1.2 +</TD> +</TR> +<TR> +<TD ALIGN="CENTER"> + [ >> ] </TD> +<TD ALIGN="CENTER"> +FastForward +</TD> +<TD> +next or up-and-next section +</TD> +<TD> +1.3 +</TD> +</TR> +<TR> +<TD ALIGN="CENTER"> + [Top] </TD> +<TD ALIGN="CENTER"> +Top +</TD> +<TD> +cover (top) of document +</TD> +<TD> + +</TD> +</TR> +<TR> +<TD ALIGN="CENTER"> + [Contents] </TD> +<TD ALIGN="CENTER"> +Contents +</TD> +<TD> +table of contents +</TD> +<TD> + +</TD> +</TR> +<TR> +<TD ALIGN="CENTER"> + [Index] </TD> +<TD ALIGN="CENTER"> +Index +</TD> +<TD> +concept index +</TD> +<TD> + +</TD> +</TR> +<TR> +<TD ALIGN="CENTER"> + [ ? ] </TD> +<TD ALIGN="CENTER"> +About +</TD> +<TD> +this page +</TD> +<TD> + +</TD> +</TR> +</TABLE> +<P></P> +where the <STRONG> Example </STRONG> assumes that the current position +is at <STRONG> Subsubsection One-Two-Three </STRONG> of a document of +the following structure: +<UL> +<LI> 1. Section One </LI> +<UL> +<LI>1.1 Subsection One-One</LI> +<UL> +<LI> ... </LI> +</UL> +<LI>1.2 Subsection One-Two</LI> +<UL> +<LI>1.2.1 Subsubsection One-Two-One +</LI><LI>1.2.2 Subsubsection One-Two-Two +</LI><LI>1.2.3 Subsubsection One-Two-Three <STRONG> +<== Current Position </STRONG> +</LI><LI>1.2.4 Subsubsection One-Two-Four +</LI></UL> +<LI>1.3 Subsection One-Three</LI> +<UL> +<LI> ... </LI> +</UL> +<LI>1.4 Subsection One-Four</LI> +</UL> +</UL> + +<HR SIZE=1> +<BR> +<FONT SIZE="-1"> +This document was generated +by <I>Chet Ramey</I> on <I>December, 29 2009</I> +using <A HREF="http://www.mathematik.uni-kl.de/~obachman/Texi2html +"><I>texi2html</I></A> + +</BODY> +</HTML> |