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F)72 458.4 R 1.405 +(or programming, Bash pro)-.15 F 1.405(vides v)-.15 F 1.405 +(ariables such as)-.25 F F2(RANDOM)3.905 E F0(and)3.905 E F2(REPL)3.905 +E(Y)-.92 E F0 3.905(,t)C(he)-3.905 E F2(typeset)3.905 E F0 -.2(bu)72 +470.4 S .398(iltin, the ability to remo).2 F .698 -.15(ve s)-.15 H .398 +(ubstrings from v).15 F .398 +(ariables based on patterns, and shell arithmetic.)-.25 F F2(RANDOM) +5.397 E F0 -.15(ex)72 482.4 S .489 +(pands to a random number each time it is referenced; assigning a v).15 +F .49(alue to)-.25 F F2(RANDOM)2.99 E F0 .49(seeds the random)2.99 F +.055(number generator)72 494.4 R(.)-.55 E F2(REPL)5.055 E(Y)-.92 E F0 +.054(is the def)2.554 F .054(ault v)-.1 F .054(ariable used by the)-.25 +F F2 -.18(re)2.554 G(ad).18 E F0 -.2(bu)2.554 G .054(iltin when no v).2 +F .054(ariable names are sup-)-.25 F .742(plied as ar)72 506.4 R 3.243 +(guments. 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Nearly)-.25 F +.222(all of)2.722 F(the operators from the C language are a)72 542.4 Q +-.25(va)-.2 G(ilable, with the same precedence rules:).25 E/F3 10 +/Courier@0 SF 6($e)97 560.4 S(cho $\(\(3 + 5 * 32\)\))-6 E(163)97 572.4 +Q F0 -.15(Fo)72 594 S 3.24(ri).15 G(nteracti)-3.24 E 1.04 -.15(ve u)-.25 +H .74(se, Bash implements ksh-style aliases and b).15 F .74 +(uiltins such as)-.2 F F2(fc)3.24 E F0 .74(\(discussed belo)3.24 F .74 +(w\) and)-.25 F F2(jobs)3.24 E F0(.)A .291(Bash aliases allo)72 606 R +2.791(was)-.25 G .291(tring to be substituted for a command name.)-2.791 +F(The)5.291 E 2.791(yc)-.15 G .291(an be used to create a mnemonic) +-2.791 F .568(for a)72 618 R/F4 9/Times-Roman@0 SF(UNIX)3.068 E F0 .568 +(command name \()3.068 F F3 .568(alias del=rm)B F0 .568(\), to e)B .567 +(xpand a single w)-.15 F .567(ord to a comple)-.1 F 3.067(xc)-.15 G .567 +(ommand \()-3.067 F F3(alias)A .255 +(news='xterm -g 80x45 -title trn -e trn -e -S1 -N &')72 630 R F0 .255 +(\), or to ensure that a command)B(is in)72 642 Q -.2(vo)-.4 G -.1(ke).2 +G 2.5(dw).1 G(ith a basic set of options \()-2.5 E F3 +(alias ls="/bin/ls -F")A F0(\).)A .293(The C shell \()97 657.6 R F2(csh) +A F0 .293(\)\207, originally written by Bill Jo)B 2.792(yw)-.1 G .292 +(hile at Berk)-2.792 F(ele)-.1 E 1.592 -.65(y, i)-.15 H 2.792(sw).65 G +.292(idely used and quite popular)-2.792 F 1.499(for its interacti)72 +669.6 R 1.799 -.15(ve f)-.25 H 3.999(acilities. Bash).05 F 1.499 +(includes a csh-compatible history e)3.999 F 1.5 +(xpansion mechanism \(\231! history\232\),)-.15 F .019(brace e)72 681.6 +R .018(xpansion, access to a stack of directories via the)-.15 F F2 +(pushd)2.518 E F0(,)A F2(popd)2.518 E F0 2.518(,a)C(nd)-2.518 E F2(dirs) +2.518 E F0 -.2(bu)2.518 G .018(iltins, and tilde e).2 F(xpansion,)-.15 E +1.293(to generate users' home directories.)72 693.6 R -.35(Ti)6.294 G +1.294(lde e).35 F 1.294(xpansion has also been adopted by both the K) +-.15 F 1.294(orn Shell and)-.35 F .32 LW 144 708.2 72 708.2 DL/F5 8 +/Times-Roman@0 SF(\207Morris Bolsk)72 720 Q 2(ya)-.12 G(nd Da)-2 E +(vid K)-.16 E(orn,)-.28 E/F6 8/Times-Italic@0 SF(The K)2 E +(ornShell Command and Pr)-.32 E -.08(og)-.36 G -.12(ra).08 G +(mming Langua).12 E -.08(ge)-.08 G F5 2(,P).08 G(rentice Hall, 1989.)-2 +E EP +%%Page: 3 3 +%%BeginPageSetup +BP +%%EndPageSetup +/F0 10/Times-Roman@0 SF(-3-)282.17 48 Q(POSIX.2.)72 84 Q .148 +(There were certain areas in which POSIX.2 felt standardization w)97 +99.6 R .149(as necessary)-.1 F 2.649(,b)-.65 G .149(ut no e)-2.849 F +.149(xisting imple-)-.15 F 1.598(mentation pro)72 111.6 R 1.598 +(vided the proper beha)-.15 F(vior)-.2 E 6.598(.T)-.55 G 1.598(he w) +-6.598 F 1.597(orking group in)-.1 F -.15(ve)-.4 G 1.597 +(nted and standardized functionality in).15 F .674 +(these areas, which Bash implements.)72 123.6 R(The)5.674 E/F1 10 +/Times-Bold@0 SF(command)3.174 E F0 -.2(bu)3.174 G .674(iltin w).2 F +.674(as in)-.1 F -.15(ve)-.4 G .674 +(nted so that shell functions could be).15 F .996(written to replace b) +72 135.6 R .996(uiltins; it mak)-.2 F .996(es the capabilities of the b) +-.1 F .995(uiltin a)-.2 F -.25(va)-.2 G .995(ilable to the function.).25 +F .995(The reserv)5.995 F(ed)-.15 E -.1(wo)72 147.6 S 1.731 +(rd \231!\232 w).1 F 1.731(as added to ne)-.1 F -.05(ga)-.15 G 1.731 +(te the return v).05 F 1.731(alue of a command or pipeline; it w)-.25 F +1.732(as nearly impossible to)-.1 F -.15(ex)72 159.6 S .286 +(press \231if not x\232 cleanly using the sh language.).15 F .286 +(There e)5.286 F .286(xist multiple incompatible implementations of the) +-.15 F F1(test)72 171.6 Q F0 -.2(bu)3.163 G .663 +(iltin, which tests \214les for type and other attrib).2 F .664 +(utes and performs arithmetic and string comparisons.)-.2 F .5 +(POSIX considered none of these correct, so the standard beha)72 183.6 R +.5(vior w)-.2 F .5(as speci\214ed in terms of the number of)-.1 F(ar)72 +195.6 Q .412(guments to the command.)-.18 F .412(POSIX.2 dictates e) +5.412 F .412(xactly what will happen when four or fe)-.15 F .412(wer ar) +-.25 F .412(guments are)-.18 F(gi)72 207.6 Q -.15(ve)-.25 G 5.01(nt).15 +G(o)-5.01 E F1(test)5.01 E F0 5.01(,a)C 2.51(nd lea)-5.01 F -.15(ve)-.2 +G 5.01(st).15 G 2.51(he beha)-5.01 F 2.51(vior unde\214ned when more ar) +-.2 F 2.51(guments are supplied.)-.18 F 2.51(Bash uses the)7.51 F +(POSIX.2 algorithm, which w)72 219.6 Q(as concei)-.1 E -.15(ve)-.25 G +2.5(db).15 G 2.5(yD)-2.5 G -.2(av)-2.5 G(id K).2 E(orn.)-.35 E F1 2.5 +(3.1. F)72 243.6 R(eatur)-.25 E(es not in the Bour)-.18 E(ne Shell)-.15 +E F0 .718(There are a number of minor dif)97 259.2 R .719 +(ferences between Bash and the v)-.25 F .719 +(ersion of sh present on most other)-.15 F -.15(ve)72 271.2 S .874 +(rsions of).15 F/F2 9/Times-Roman@0 SF(UNIX)3.374 E F0 5.873(.T)C .873 +(he majority of these are due to the POSIX standard, b)-5.873 F .873 +(ut some are the result of Bash)-.2 F .386 +(adopting features from other shells.)72 283.2 R -.15(Fo)5.386 G 2.886 +(ri).15 G .386(nstance, Bash includes the ne)-2.886 F 2.886<7799>-.25 G +.386(!\232 reserv)-2.886 F .386(ed w)-.15 F .386(ord, the)-.1 F F1 +(command)2.886 E F0 -.2(bu)72 295.2 S .116(iltin, the ability of the).2 +F F1 -.18(re)2.616 G(ad).18 E F0 -.2(bu)2.615 G .115 +(iltin to correctly return a line ending with a backslash, symbolic ar) +.2 F(guments)-.18 E .798(to the)72 307.2 R F1(umask)3.298 E F0 -.2(bu) +3.298 G .798(iltin, v).2 F .798(ariable substring remo)-.25 F -.25(va) +-.15 G .798(l, a w).25 F .799(ay to get the length of a v)-.1 F .799 +(ariable, and the ne)-.25 F 3.299(wa)-.25 G(lgo-)-3.299 E(rithm for the) +72 319.2 Q F1(test)2.5 E F0 -.2(bu)2.5 G +(iltin from the POSIX.2 standard, none of which appear in sh.).2 E 1.225 +(Bash also implements the \231$\(...\)\232 command substitution syntax,\ + which supersedes the sh `...` con-)97 334.8 R 2.851(struct. The)72 +346.8 R .351(\231$\(...\)\232 construct e)2.851 F .351(xpands to the ou\ +tput of the command contained within the parentheses, with)-.15 F .664 +(trailing ne)72 358.8 R .664(wlines remo)-.25 F -.15(ve)-.15 G 3.164 +(d. The).15 F .664(sh syntax is accepted for backw)3.164 F .664 +(ards compatibility)-.1 F 3.164(,b)-.65 G .664 +(ut the \231$\(...\)\232 form is)-3.364 F(preferred because its quoting\ + rules are much simpler and it is easier to nest.)72 370.8 Q .772 +(The Bourne shell does not pro)97 386.4 R .772 +(vide such features as brace e)-.15 F .772 +(xpansion, the ability to de\214ne a v)-.15 F(ariable)-.25 E .283 +(and a function with the same name, local v)72 398.4 R .282 +(ariables in shell functions, the ability to enable and disable indi-) +-.25 F .547(vidual b)72 410.4 R .547 +(uiltins or write a function to replace a b)-.2 F .547 +(uiltin, or a means to e)-.2 F .547 +(xport a shell function to a child pro-)-.15 F(cess.)72 422.4 Q .32 +(Bash has closed a long-standing shell security hole by not using the)97 +438 R F1($IFS)2.82 E F0 -.25(va)2.82 G .32(riable to split each w).25 F +(ord)-.1 E 1.254(read by the shell, b)72 450 R 1.254 +(ut splitting only the results of e)-.2 F 1.255 +(xpansion \(ksh and the 4.4 BSD sh ha)-.15 F 1.555 -.15(ve \214)-.2 H +-.15(xe).15 G 3.755(dt).15 G 1.255(his as)-3.755 F 2.907(well\). Useful) +72 462 R(beha)2.907 E .407(vior such as a means to abort e)-.2 F -.15 +(xe)-.15 G .407(cution of a script read with the \231.).15 F 2.906<9a63> +-.7 G .406(ommand using the)-2.906 F F1 -.18(re)72 474 S(tur).18 E(n) +-.15 E F0 -.2(bu)2.742 G .242(iltin or automatically e).2 F .242 +(xporting v)-.15 F .243(ariables in the shell')-.25 F 2.743(se)-.55 G +-.4(nv)-2.743 G .243(ironment to children is also not present).4 F .969 +(in the Bourne shell.)72 486 R .968(Bash pro)5.968 F .968 +(vides a much more po)-.15 F .968(werful en)-.25 F .968 +(vironment for both interacti)-.4 F 1.268 -.15(ve u)-.25 H .968 +(se and pro-).15 F(gramming.)72 498 Q F1 2.5(4. Bash-speci\214c)72 522 R +-.25(Fe)2.5 G(atur).25 E(es)-.18 E F0 .491(This section details a fe)97 +537.6 R 2.991(wo)-.25 G 2.991(ft)-2.991 G .491(he features which mak) +-2.991 F 2.991(eB)-.1 G .491(ash unique.)-2.991 F .492(Most of them pro) +5.491 F .492(vide impro)-.15 F -.15(ve)-.15 G(d).15 E(interacti)72 549.6 +Q 1.182 -.15(ve u)-.25 H .882(se, b).15 F .882(ut a fe)-.2 F 3.382(wp) +-.25 G .882(rogramming impro)-3.382 F -.15(ve)-.15 G .882 +(ments are present as well.).15 F .882(Full descriptions of these fea-) +5.882 F(tures can be found in the Bash documentation.)72 561.6 Q F1 2.5 +(4.1. Startup)72 585.6 R(Files)2.5 E F0 .161(Bash e)97 601.2 R -.15(xe) +-.15 G .161(cutes startup \214les dif).15 F .161 +(ferently than other shells.)-.25 F .162(The Bash beha)5.161 F .162 +(vior is a compromise between)-.2 F .29 +(the csh principle of startup \214les with \214x)72 613.2 R .29 +(ed names e)-.15 F -.15(xe)-.15 G .29 +(cuted for each shell and the sh \231minimalist\232 beha).15 F(vior)-.2 +E(.)-.55 E 2.955(An interacti)72 625.2 R 3.255 -.15(ve i)-.25 H 2.955 +(nstance of Bash started as a login shell reads and e).15 F -.15(xe)-.15 +G(cutes).15 E/F3 10/Times-Italic@0 SF(~/.bash_pr)5.456 E(o\214le)-.45 E +F0 2.956(\(the \214le)5.456 F .954(.bash_pro\214le in the user')72 637.2 +R 3.454(sh)-.55 G .953(ome directory\), if it e)-3.454 F 3.453 +(xists. An)-.15 F(interacti)3.453 E 1.253 -.15(ve n)-.25 H .953 +(on-login shell reads and e).15 F -.15(xe)-.15 G(cutes).15 E F3 +(~/.bashr)72 649.2 Q(c)-.37 E F0 5.641(.A)C(non-interacti)-2.5 E .942 +-.15(ve s)-.25 H .642(hell \(one be).15 F .642(gun to e)-.15 F -.15(xe) +-.15 G .642(cute a shell script, for e).15 F .642 +(xample\) reads no \214x)-.15 F .642(ed startup)-.15 F .342(\214le, b)72 +661.2 R .342(ut uses the v)-.2 F .342(alue of the v)-.25 F(ariable)-.25 +E F1($ENV)2.842 E F0 2.841(,i)C 2.841(fs)-2.841 G .341 +(et, as the name of a startup \214le.)-2.841 F .341 +(The ksh practice of read-)5.341 F(ing)72 673.2 Q F1($ENV)3.114 E F0 +.614(for e)3.114 F -.15(ve)-.25 G .614(ry shell, with the accompan).15 F +.615(ying dif)-.15 F .615(\214culty of de\214ning the proper v)-.25 F +.615(ariables and functions)-.25 F .721(for interacti)72 685.2 R 1.021 +-.15(ve a)-.25 H .721(nd non-interacti).15 F 1.021 -.15(ve s)-.25 H .721 +(hells or ha).15 F .721(ving the \214le read only for interacti)-.2 F +1.02 -.15(ve s)-.25 H .72(hells, w).15 F .72(as considered)-.1 F .158 +(too comple)72 697.2 R 2.658(x. Ease)-.15 F .158(of use w)2.658 F .158 +(on out here.)-.1 F(Interestingly)5.158 E 2.658(,t)-.65 G .158(he ne) +-2.658 F .159(xt release of ksh will change to reading)-.15 F F1($ENV) +2.659 E .32 LW 144 705.2 72 705.2 DL/F4 8/Times-Roman@0 SF .559 +(\207Bill Jo)72 717 R 1.599 -.52(y, A)-.08 H 2.559(nI).52 G .559 +(ntroduction to the C Shell,)-2.559 F/F5 8/Times-Italic@0 SF .558 +(UNIX User')2.558 F 2.558(sS)-.32 G .558(upplementary Documents)-2.558 F +F4 2.558(,U)C(ni)-2.558 E -.12(ve)-.2 G .558(rsity of California at).12 +F(Berk)72 727 Q(ele)-.08 E 1.04 -.52(y, 1)-.12 H(986.).52 E EP +%%Page: 4 4 +%%BeginPageSetup +BP +%%EndPageSetup +/F0 10/Times-Roman@0 SF(-4-)282.17 48 Q(only for interacti)72 84 Q .3 +-.15(ve s)-.25 H(hells.).15 E/F1 10/Times-Bold@0 SF 2.5(4.2. New)72 108 +R(Builtin Commands)2.5 E F0 1.02(There are a fe)97 123.6 R 3.52(wb)-.25 +G 1.02(uiltins which are ne)-3.72 F 3.52(wo)-.25 G 3.52(rh)-3.52 G -2.25 +-.2(av e)-3.52 H 1.02(been e)3.72 F 1.02(xtended in Bash.)-.15 F(The) +6.02 E F1(enable)3.52 E F0 -.2(bu)3.52 G 1.02(iltin allo).2 F(ws)-.25 E +-.2(bu)72 135.6 S .824(iltin commands to be turned on and of).2 F 3.324 +(fa)-.25 G(rbitrarily)-3.324 E 5.824(.T)-.65 G 3.324(ou)-6.624 G .824 +(se the v)-3.324 F .824(ersion of)-.15 F/F2 10/Times-Italic@0 SF(ec) +3.324 E(ho)-.15 E F0 .825(found in a user')3.324 F 3.325(ss)-.55 G +(earch)-3.325 E .625(path rather than the Bash b)72 147.6 R(uiltin,)-.2 +E/F3 10/Courier@0 SF .625(enable -n echo)3.125 F F0(suf)3.125 E 3.125 +(\214ces. The)-.25 F F1(help)3.124 E F0 -.2(bu)3.124 G .624(iltin pro).2 +F .624(vides quick synopses)-.15 F .703(of the shell f)72 159.6 R .704 +(acilities without requiring access to a manual page.)-.1 F F1(Builtin) +5.704 E F0 .704(is similar to)3.204 F F1(command)3.204 E F0 .704 +(in that it)3.204 F .342(bypasses shell functions and directly e)72 +171.6 R -.15(xe)-.15 G .342(cutes b).15 F .342(uiltin commands.)-.2 F +.342(Access to a csh-style stack of directories)5.342 F .072(is pro)72 +183.6 R .073(vided via the)-.15 F F1(pushd)2.573 E F0(,)A F1(popd)2.573 +E F0 2.573(,a)C(nd)-2.573 E F1(dirs)2.573 E F0 -.2(bu)2.573 G(iltins.).2 +E F1(Pushd)5.073 E F0(and)2.573 E F1(popd)2.573 E F0 .073 +(insert and remo)2.573 F .373 -.15(ve d)-.15 H .073(irectories from the) +.15 F 2.858(stack, respecti)72 195.6 R -.15(ve)-.25 G(ly).15 E 5.358(,a) +-.65 G(nd)-5.358 E F1(dirs)5.358 E F0 2.858(lists the stack contents.) +5.358 F 2.858(On systems that allo)7.858 F 5.358<778c>-.25 G 2.857 +(ne-grained control of)-5.358 F 1.339(resources, the)72 207.6 R F1 +(ulimit)3.839 E F0 -.2(bu)3.839 G 1.339 +(iltin can be used to tune these settings.).2 F F1(Ulimit)6.34 E F0 +(allo)3.84 E 1.34(ws a user to control, among)-.25 F 1.086 +(other things, whether core dumps are to be generated, ho)72 219.6 R +3.586(wm)-.25 G 1.086(uch memory the shell or a child process is)-3.586 +F(allo)72 231.6 Q .496(wed to allocate, and ho)-.25 F 2.996(wl)-.25 G +(ar)-2.996 E .496(ge a \214le created by a child process can gro)-.18 F +4.296 -.65(w. T)-.25 H(he).65 E F1(suspend)2.996 E F0 .497(command will) +2.997 F .744(stop the shell process when job control is acti)72 243.6 R +-.15(ve)-.25 G 3.243(;m).15 G .743(ost other shells do not allo)-3.243 F +3.243(wt)-.25 G(hemselv)-3.243 E .743(es to be stopped)-.15 F(lik)72 +255.6 Q 2.717(et)-.1 G(hat.)-2.717 E F1 -.74(Ty)5.217 G(pe,).74 E F0 +.217(the Bash answer to)2.717 F F1(which)2.717 E F0(and)2.717 E F1 +(whence,)2.717 E F0(sho)2.717 E .218(ws what will happen when a w)-.25 F +.218(ord is typed as a)-.1 F(command:)72 267.6 Q F3 6($t)97 285.6 S +(ype export)-6 E(export is a shell builtin)97 297.6 Q 6($t)97 309.6 S +(ype -t export)-6 E(builtin)97 321.6 Q 6($t)97 333.6 S(ype bash)-6 E +(bash is /bin/bash)97 345.6 Q 6($t)97 357.6 S(ype cd)-6 E +(cd is a function)97 369.6 Q(cd \(\))97 381.6 Q({)97 393.6 Q +(builtin cd ${1+"$@"} && xtitle $HOST: $PWD)121 405.6 Q(})97 417.6 Q F0 +-1.11(Va)72 439.2 S .682(rious modes tell what a command w)1.11 F .681 +(ord is \(reserv)-.1 F .681(ed w)-.15 F .681(ord, alias, function, b)-.1 +F .681(uiltin, or \214le\) or which v)-.2 F(er)-.15 E(-)-.2 E 1.15 +(sion of a command will be e)72 451.2 R -.15(xe)-.15 G 1.15 +(cuted based on a user').15 F 3.65(ss)-.55 G 1.15(earch path.)-3.65 F +1.15(Some of this functionality has been)6.15 F +(adopted by POSIX.2 and folded into the)72 463.2 Q F1(command)2.5 E F0 +(utility)2.5 E(.)-.65 E F1 2.5(4.3. Editing)72 487.2 R(and Completion) +2.5 E F0 .682(One area in which Bash shines is command line editing.)97 +502.8 R .682(Bash uses the)5.682 F F2 -.37(re)3.182 G(adline).37 E F0 +.681(library to read and)3.181 F .942(edit lines when interacti)72 514.8 +R -.15(ve)-.25 G 5.942(.R).15 G .942(eadline is a po)-5.942 F .942 +(werful and \215e)-.25 F .942(xible input f)-.15 F .943 +(acility that a user can con\214gure to)-.1 F(indi)72 526.8 Q .732 +(vidual tastes.)-.25 F .732(It allo)5.732 F .732(ws lines to be edited \ +using either emacs or vi commands, where those commands)-.25 F .2 +(are appropriate.)72 538.8 R .2 +(The full capability of emacs is not present \255 there is no w)5.2 F .2 +(ay to e)-.1 F -.15(xe)-.15 G .2(cute a named command).15 F 1.15 +(with M-x, for instance \255 b)72 550.8 R 1.15(ut the e)-.2 F 1.149 +(xisting commands are more than adequate.)-.15 F 1.149 +(The vi mode is compliant)6.149 F +(with the command line editing standardized by POSIX.2.)72 562.8 Q 1.69 +(Readline is fully customizable.)97 578.4 R 1.691 +(In addition to the basic commands and k)6.69 F 1.991 -.15(ey b)-.1 H +1.691(indings, the library).15 F(allo)72 590.4 Q .028 +(ws users to de\214ne additional k)-.25 F .327 -.15(ey b)-.1 H .027 +(indings using a startup \214le.).15 F(The)5.027 E F2(inputr)2.527 E(c) +-.37 E F0 .027(\214le, which def)2.527 F .027(aults to the \214le)-.1 F +F2(~/.inputr)72 602.4 Q(c)-.37 E F0 3.002(,i)C 3.002(sr)-3.002 G .503(e\ +ad each time readline initializes, permitting users to maintain a consi\ +stent interf)-3.002 F .503(ace across a)-.1 F .893(set of programs.)72 +614.4 R .893(Readline includes an e)5.893 F .893(xtensible interf)-.15 F +.892(ace, so each program using the library can add its)-.1 F -.25(ow)72 +626.4 S 3.56(nb).25 G 1.06(indable commands and program-speci\214c k) +-3.56 F 1.361 -.15(ey b)-.1 H 3.561(indings. Bash).15 F 1.061 +(uses this f)3.561 F 1.061(acility to add bindings that)-.1 F +(perform history e)72 638.4 Q(xpansion or shell w)-.15 E(ord e)-.1 E +(xpansions on the current input line.)-.15 E .707 +(Readline interprets a number of v)97 654 R .706 +(ariables which further tune its beha)-.25 F(vior)-.2 E 5.706(.V)-.55 G +.706(ariables e)-6.816 F .706(xist to control)-.15 F .157 +(whether or not eight-bit characters are directly read as input or con) +72 666 R -.15(ve)-.4 G .158(rted to meta-pre\214x).15 F .158(ed k)-.15 F +.458 -.15(ey s)-.1 H .158(equences \(a).15 F(meta-pre\214x)72 678 Q .082 +(ed k)-.15 F .382 -.15(ey s)-.1 H .081(equence consists of the characte\ +r with the eighth bit zeroed, preceded by the).15 F F2(meta-pr)2.581 E +(e\214x)-.37 E F0(character)72 690 Q 3.233(,u)-.4 G .733 +(sually escape, which selects an alternate k)-3.233 F -.15(ey)-.1 G .734 +(map\), to decide whether to output characters with).15 F .624 +(the eighth bit set directly or as a meta-pre\214x)72 702 R .624(ed k) +-.15 F .924 -.15(ey s)-.1 H .623 +(equence, whether or not to wrap to a ne).15 F 3.123(ws)-.25 G .623 +(creen line)-3.123 F 1.196 +(when a line being edited is longer than the screen width, the k)72 714 +R -.15(ey)-.1 G 1.196(map to which subsequent k).15 F 1.496 -.15(ey b) +-.1 H(indings).15 E .531(should apply)72 726 R 3.031(,o)-.65 G 3.031(re) +-3.031 G -.15(ve)-3.281 G 3.031(nw).15 G .531 +(hat happens when readline w)-3.031 F .531(ants to ring the terminal') +-.1 F 3.03(sb)-.55 G 3.03(ell. All)-3.03 F .53(of these v)3.03 F +(ariables)-.25 E EP +%%Page: 5 5 +%%BeginPageSetup +BP +%%EndPageSetup +/F0 10/Times-Roman@0 SF(-5-)282.17 48 Q +(can be set in the inputrc \214le.)72 84 Q .284 +(The startup \214le understands a set of C preprocessor)97 99.6 R(-lik) +-.2 E 2.785(ec)-.1 G .285(onditional constructs which allo)-2.785 F +2.785(wv)-.25 G(ariables)-3.035 E .12(or k)72 111.6 R .42 -.15(ey b)-.1 +H .119(indings to be assigned based on the application using readline, \ +the terminal currently being used, or).15 F .338(the editing mode.)72 +123.6 R .338(Users can add program-speci\214c bindings to mak)5.338 F +2.838(et)-.1 G .338(heir li)-2.838 F -.15(ve)-.25 G 2.838(se).15 G 2.838 +(asier: I)-2.838 F(ha)2.838 E .639 -.15(ve b)-.2 H .339(indings that).15 +F(let me edit the v)72 135.6 Q(alue of)-.25 E/F1 10/Times-Bold@0 SF($P) +2.5 E -.95(AT)-.74 G(H).95 E F0(and double-quote the current or pre)2.5 +E(vious w)-.25 E(ord:)-.1 E/F2 10/Courier@0 SF 6(#M)97 153.6 S +(acros that are convenient for shell interaction)-6 E($if Bash)97 165.6 +Q 6(#e)97 177.6 S(dit the path)-6 E +("\\C-xp": "PATH=${PATH}\\e\\C-e\\C-a\\ef\\C-f")97 189.6 Q 6(#p)97 201.6 +S(repare to type a quoted word -- insert open and close double)-6 E 6 +(#q)97 213.6 S(uotes and move to just after the open quote)-6 E +("\\C-x\\"": "\\"\\"\\C-b")97 225.6 Q 6(#Q)97 237.6 S +(uote the current or previous word)-6 E("\\C-xq": "\\eb\\"\\ef\\"")97 +249.6 Q($endif)97 261.6 Q F0 .322(There is a readline command to re-rea\ +d the \214le, so users can edit the \214le, change some bindings, and b\ +e)72 283.2 R(gin)-.15 E(to use them almost immediately)72 295.2 Q(.)-.65 +E .851(Bash implements the)97 310.8 R F1(bind)3.351 E F0 -.2(bu)3.351 G +.851(iltin for more dyamic control of readline than the startup \214le \ +permits.).2 F F1(Bind)72 322.8 Q F0 .25(is used in se)2.75 F -.15(ve) +-.25 G .25(ral w).15 F 2.75(ays. In)-.1 F/F3 10/Times-Italic@0 SF(list) +2.75 E F0 .25(mode, it can display the current k)2.75 F .55 -.15(ey b) +-.1 H .25(indings, list all the readline edit-).15 F .149(ing directi)72 +334.8 R -.15(ve)-.25 G 2.649(sa).15 G -.25(va)-2.849 G .149 +(ilable for binding, list which k).25 F -.15(ey)-.1 G 2.649(si).15 G +-1.9 -.4(nv o)-2.649 H .349 -.1(ke a g).4 H -2.15 -.25(iv e).1 H 2.65 +(nd).25 G(irecti)-2.65 E -.15(ve)-.25 G 2.65(,o).15 G 2.65(ro)-2.65 G +.15(utput the current set of k)-2.65 F -.15(ey)-.1 G .042(bindings in a\ + format that can be incorporated directly into an inputrc \214le.)72 +346.8 R(In)5.041 E F3(batc)2.541 E(h)-.15 E F0 .041 +(mode, it reads a series of)2.541 F -.1(ke)72 358.8 S 2.858(yb)-.05 G +.359(indings directly from a \214le and passes them to readline.)-2.858 +F .359(In its most common usage,)5.359 F F1(bind)2.859 E F0(tak)2.859 E +.359(es a sin-)-.1 F 1.117(gle string and passes it directly to readlin\ +e, which interprets the line as if it had just been read from the)72 +370.8 R(inputrc \214le.)72 382.8 Q(Both k)5 E .3 -.15(ey b)-.1 H +(indings and v).15 E(ariable assignments may appear in the string gi) +-.25 E -.15(ve)-.25 G 2.5(nt).15 G(o)-2.5 E F1(bind)2.5 E F0(.)A .53 +(The readline library also pro)97 398.4 R .53(vides an interf)-.15 F .53 +(ace for)-.1 F F3(wor)3.03 E 3.03(dc)-.37 G(ompletion)-3.03 E F0 5.53 +(.W)C .53(hen the)-5.53 F F3(completion)3.03 E F0(character)3.03 E 1.261 +(\(usually T)72 410.4 R 1.261(AB\) is typed, readline looks at the w) +-.93 F 1.26(ord currently being entered and computes the set of \214le-) +-.1 F .523(names of which the current w)72 422.4 R .523(ord is a v)-.1 F +.523(alid pre\214x.)-.25 F .524 +(If there is only one possible completion, the rest of the)5.523 F .358 +(characters are inserted directly)72 434.4 R 2.858(,o)-.65 G .358(therw\ +ise the common pre\214x of the set of \214lenames is added to the curre\ +nt)-2.858 F -.1(wo)72 446.4 S 3.199(rd. A).1 F .699(second T)3.199 F +.699(AB character entered immediately after a non-unique completion cau\ +ses readline to list)-.93 F 1.814 +(the possible completions; there is an option to ha)72 458.4 R 2.113 +-.15(ve t)-.2 H 1.813(he list displayed immediately).15 F 6.813(.R)-.65 +G 1.813(eadline pro)-6.813 F(vides)-.15 E .482 +(hooks so that applications can pro)72 470.4 R .482 +(vide speci\214c types of completion before the def)-.15 F .483 +(ault \214lename completion)-.1 F .132(is attempted.)72 482.4 R .132 +(This is quite \215e)5.132 F .132 +(xible, though it is not completely user)-.15 F 2.632 +(-programmable. Bash,)-.2 F .132(for e)2.632 F .132(xample, can)-.15 F +.37(complete \214lenames, command names \(including aliases, b)72 494.4 +R .37(uiltins, shell reserv)-.2 F .37(ed w)-.15 F .37 +(ords, shell functions, and)-.1 F -.15(exe)72 506.4 S .424 +(cutables found in the \214le system\), shell v).15 F .424 +(ariables, usernames, and hostnames.)-.25 F .423 +(It uses a set of heuristics)5.424 F(that, while not perfect, is genera\ +lly quite good at determining what type of completion to attempt.)72 +518.4 Q F1 2.5(4.4. History)72 542.4 R F0 .144 +(Access to the list of commands pre)97 558 R .144(viously entered \(the) +-.25 F F3 .144(command history)2.644 F F0 2.644(\)i)C 2.644(sp)-2.644 G +(ro)-2.644 E .144(vided jointly by Bash)-.15 F .078 +(and the readline library)72 570 R 5.077(.B)-.65 G .077(ash pro)-5.077 F +.077(vides v)-.15 F .077(ariables \()-.25 F F1($HISTFILE)A F0(,)A F1 +($HISTSIZE)2.577 E F0 2.577(,a)C(nd)-2.577 E F1($HISTCONTR)2.577 E(OL) +-.3 E F0 2.577(\)a)C(nd)-2.577 E(the)72 582 Q F1(history)2.89 E F0(and) +2.89 E F1(fc)2.89 E F0 -.2(bu)2.89 G .39 +(iltins to manipulate the history list.).2 F .391(The v)5.391 F .391 +(alue of)-.25 F F1($HISTFILE)2.891 E F0 .391(specifes the \214le where) +2.891 F .49(Bash writes the command history on e)72 594 R .489 +(xit and reads it on startup.)-.15 F F1($HISTSIZE)5.489 E F0 .489 +(is used to limit the number)2.989 F .642(of commands sa)72 606 R -.15 +(ve)-.2 G 3.142(di).15 G 3.142(nt)-3.142 G .642(he history)-3.142 F(.) +-.65 E F1($HISTCONTR)5.642 E(OL)-.3 E F0(pro)3.142 E .642 +(vides a crude form of control o)-.15 F -.15(ve)-.15 G 3.142(rw).15 G +.642(hich com-)-3.142 F .025(mands are sa)72 618 R -.15(ve)-.2 G 2.525 +(do).15 G 2.525(nt)-2.525 G .025(he history list: a v)-2.525 F .025 +(alue of)-.25 F F3(ignor)2.525 E(espace)-.37 E F0 .025(means to not sa) +2.525 F .324 -.15(ve c)-.2 H .024(ommands which be).15 F .024 +(gin with a)-.15 F .927(space; a v)72 630 R .927(alue of)-.25 F F3 +(ignor)3.427 E(edups)-.37 E F0 .927(means to not sa)3.427 F 1.228 -.15 +(ve c)-.2 H .928(ommands identical to the last command sa).15 F -.15(ve) +-.2 G(d.).15 E F1($HIST)5.928 E(-)-.92 E(CONTR)72 642 Q(OL)-.3 E F0 -.1 +(wa)3.778 G 3.778(sn).1 G(amed)-3.778 E F1($history_contr)3.778 E(ol) +-.18 E F0 1.278(in earlier v)3.778 F 1.278 +(ersions of Bash; the old name is still accepted for)-.15 F(backw)72 654 +Q .575(ards compatibility)-.1 F 5.575(.T)-.65 G(he)-5.575 E F1(history) +3.075 E F0 .575 +(command can read or write \214les containing the history list and dis-) +3.075 F .167(play the current list contents.)72 666 R(The)5.167 E F1(fc) +2.667 E F0 -.2(bu)2.667 G .167(iltin, adopted from POSIX.2 and the K).2 +F .167(orn Shell, allo)-.35 F .167(ws display and)-.25 F(re-e)72 678 Q +-.15(xe)-.15 G .58 +(cution, with optional editing, of commands from the history list.).15 F +.58(The readline library of)5.58 F .58(fers a set of)-.25 F 1.255(comma\ +nds to search the history list for a portion of the current input line \ +or a string typed by the user)72 690 R(.)-.55 E(Finally)72 702 Q 2.535 +(,t)-.65 G(he)-2.535 E F3(history)2.535 E F0(library)2.535 E 2.535(,g) +-.65 G .036(enerally incorporated directly into the readline library) +-2.535 F 2.536(,i)-.65 G .036(mplements a f)-2.536 F .036(acility for) +-.1 F 1.023(history recall, e)72 714 R 1.022(xpansion, and re-e)-.15 F +-.15(xe)-.15 G 1.022(cution of pre).15 F 1.022(vious commands v)-.25 F +1.022(ery similar to csh \(\231bang history\232, so)-.15 F +(called because the e)72 726 Q +(xclamation point introduces a history substitution\):)-.15 E EP +%%Page: 6 6 +%%BeginPageSetup +BP +%%EndPageSetup +/F0 10/Times-Roman@0 SF(-6-)282.17 48 Q/F1 10/Courier@0 SF 6($e)97 84 S +(cho a b c d e)-6 E 6(abcde)97 96 S 6($!)97 108 S 6(!fghi)-6 G +(echo a b c d e f g h i)97 120 Q 6(abcdefghi)97 132 S 6($!)97 144 S(-2) +-6 E(echo a b c d e)97 156 Q 6(abcde)97 168 S 6($e)97 180 S(cho !-2:1-4) +-6 E(echo a b c d)97 192 Q 6(abcd)97 204 S F0 1.456 +(The command history is only sa)72 225.6 R -.15(ve)-.2 G 3.957(dw).15 G +1.457(hen the shell is interacti)-3.957 F -.15(ve)-.25 G 3.957(,s).15 G +3.957(oi)-3.957 G 3.957(ti)-3.957 G 3.957(sn)-3.957 G 1.457(ot a)-3.957 +F -.25(va)-.2 G 1.457(ilable for use by shell).25 F(scripts.)72 237.6 Q +/F2 10/Times-Bold@0 SF 2.5(4.5. New)72 261.6 R(Shell V)2.5 E(ariables) +-.92 E F0 .59(There are a number of con)97 277.2 R -.15(ve)-.4 G .589 +(nience v).15 F .589(ariables that Bash interprets to mak)-.25 F 3.089 +(el)-.1 G .589(ife easier)-3.089 F 5.589(.T)-.55 G .589(hese include) +-5.589 F F2(FIGNORE)72 289.2 Q F0 3.973(,w)C 1.473 +(hich is a set of \214lename suf)-3.973 F<8c78>-.25 E 1.474 +(es identifying \214les to e)-.15 F 1.474 +(xclude when completing \214lenames;)-.15 F F2(HOSTTYPE)72 301.2 Q F0 +2.932(,w)C .432 +(hich is automatically set to a string describing the type of hardw) +-2.932 F .431(are on which Bash is cur)-.1 F(-)-.2 E .335(rently e)72 +313.2 R -.15(xe)-.15 G(cuting;).15 E F2(command_oriented_history)2.835 E +F0 2.835(,w)C .335(hich directs Bash to sa)-2.835 F .635 -.15(ve a)-.2 H +.336(ll lines of a multiple-line com-).15 F 1.071(mand such as a)72 +325.2 R/F3 10/Times-Italic@0 SF(while)3.571 E F0(or)3.571 E F3(for)3.571 +E F0 1.071(loop in a single history entry)3.571 F 3.57(,a)-.65 G(llo) +-3.57 E 1.07(wing easy re-editing; and)-.25 F F2(IGNOREEOF)3.57 E F0(,)A +.747(whose v)72 337.2 R .747(alue indicates the number of consecuti)-.25 +F 1.047 -.15(ve E)-.25 H .747(OF characters that an interacti).15 F +1.048 -.15(ve s)-.25 H .748(hell will read before).15 F -.15(ex)72 349.2 +S 1.432(iting \255 an easy w).15 F 1.432(ay to k)-.1 F 1.432 +(eep yourself from being logged out accidentally)-.1 F 6.432(.T)-.65 G +(he)-6.432 E F2(auto_r)3.932 E(esume)-.18 E F0 -.25(va)3.932 G(riable) +.25 E .571(alters the w)72 361.2 R .571 +(ay the shell treats simple command names: if job control is acti)-.1 F +-.15(ve)-.25 G 3.071(,a).15 G .571(nd this v)-3.071 F .571 +(ariable is set, sin-)-.25 F(gle-w)72 373.2 Q .239(ord simple commands \ +without redirections cause the shell to \214rst look for and restart a \ +suspended job)-.1 F(with that name before starting a ne)72 385.2 Q 2.5 +(wp)-.25 G(rocess.)-2.5 E F2 2.5(4.6. Brace)72 409.2 R(Expansion)2.5 E +F0 .653(Since sh of)97 424.8 R .653(fers no con)-.25 F -.15(ve)-.4 G +.653(nient w).15 F .653 +(ay to generate arbitrary strings that share a common pre\214x or suf) +-.1 F<8c78>-.25 E 2.124(\(\214lename e)72 436.8 R 2.124 +(xpansion requires that the \214lenames e)-.15 F 2.123 +(xist\), Bash implements)-.15 F F3(br)4.623 E 2.123(ace e)-.15 F +(xpansion)-.2 E F0 4.623(,ac)C(apability)-4.623 E(pick)72 448.8 Q .773 +(ed up from csh.)-.1 F .774(Brace e)5.773 F .774 +(xpansion is similar to \214lename e)-.15 F .774(xpansion, b)-.15 F .774 +(ut the strings generated need not)-.2 F 1.211(correspond to e)72 460.8 +R 1.211(xisting \214les.)-.15 F 3.711(Ab)6.211 G 1.211(race e)-3.711 F +1.211(xpression consists of an optional)-.15 F F3(pr)3.71 E(eamble)-.37 +E F0 3.71(,f)C(ollo)-3.71 E 1.21(wed by a pair of)-.25 F 2.938 +(braces enclosing a series of comma-separated strings, and an optional) +72 472.8 R F3(postamble)5.438 E F0 7.938(.T)C 2.938(he preamble is) +-7.938 F(prepended to each string within the braces, and the postamble \ +is then appended to each resulting string:)72 484.8 Q F1 6($e)97 502.8 S +(cho a{d,c,b}e)-6 E(ade ace abe)97 514.8 Q F0 .306(As this e)72 536.4 R +.306(xample demonstrates, the results of brace e)-.15 F .305 +(xpansion are not sorted, as the)-.15 F 2.805(ya)-.15 G .305 +(re by \214lename e)-2.805 F(xpan-)-.15 E(sion.)72 548.4 Q F2 2.5 +(4.7. Pr)72 572.4 R(ocess Substitution)-.18 E F0 .457 +(On systems that can support it, Bash pro)97 588 R .457(vides a f)-.15 F +.457(acility kno)-.1 F .458(wn as)-.25 F F3(pr)2.958 E .458 +(ocess substitution)-.45 F F0 5.458(.P)C .458(rocess sub-)-5.458 F .347 +(stitution is similar to command substitution in that its speci\214cati\ +on includes a command to e)72 600 R -.15(xe)-.15 G .346(cute, b).15 F +.346(ut the)-.2 F .181(shell does not collect the command')72 612 R +2.681(so)-.55 G .181(utput and insert it into the command line.)-2.681 F +(Rather)5.181 E 2.681(,B)-.4 G .182(ash opens a pipe)-2.681 F 1.861 +(to the command, which is run in the background.)72 624 R 1.861 +(The shell uses named pipes \(FIFOs\) or the)6.861 F F3(/de)4.361 E +(v/fd)-.15 E F0 .961(method of naming open \214les to e)72 636 R .962(x\ +pand the process substitution to a \214lename which connects to the pip\ +e)-.15 F .104(when opened.)72 648 R .103 +(This \214lename becomes the result of the e)5.104 F 2.603 +(xpansion. Process)-.15 F .103(substitution can be used to com-)2.603 F +(pare the outputs of tw)72 660 Q 2.5(od)-.1 G(if)-2.5 E(ferent v)-.25 E +(ersions of an application as part of a re)-.15 E(gression test:)-.15 E +F1 6($c)97 678 S(mp <\(old_prog\) <\(new_prog\))-6 E EP +%%Page: 7 7 +%%BeginPageSetup +BP +%%EndPageSetup +/F0 10/Times-Roman@0 SF(-7-)282.17 48 Q/F1 10/Times-Bold@0 SF 2.5 +(4.8. Pr)72 84 R(ompt Customization)-.18 E F0 2.229 +(One of the more popular interacti)97 99.6 R 2.529 -.15(ve f)-.25 H +2.229(eatures that Bash pro).15 F 2.23 +(vides is the ability to customize the)-.15 F 3.234(prompt. Both)72 +111.6 R F1($PS1)3.234 E F0(and)3.234 E F1($PS2,)3.234 E F0 .734 +(the primary and secondary prompts, are e)3.234 F .733 +(xpanded before being displayed.)-.15 F -.15(Pa)72 123.6 S .804 +(rameter and v).15 F .804(ariable e)-.25 F .805 +(xpansion is performed when the prompt string is e)-.15 F .805 +(xpanded, so an)-.15 F 3.305(ys)-.15 G .805(hell v)-3.305 F(ariable)-.25 +E .729(can be put into the prompt \(e.g.,)72 135.6 R F1($SHL)3.228 E(VL) +-.92 E F0 3.228(,w)C .728(hich indicates ho)-3.228 F 3.228(wd)-.25 G +.728(eeply the current shell is nested\).)-3.228 F(Bash)5.728 E 1.895(s\ +pecially interprets characters in the prompt string preceded by a backs\ +lash.)72 147.6 R 1.895(Some of these backslash)6.895 F .874 +(escapes are replaced with the current time, the date, the current w)72 +159.6 R .874(orking directory)-.1 F 3.373(,t)-.65 G .873 +(he username, and the)-3.373 F .78 +(command number or history number of the command being entered.)72 171.6 +R .781(There is e)5.781 F -.15(ve)-.25 G 3.281(nab).15 G .781 +(ackslash escape to)-3.281 F .007 +(cause the shell to change its prompt when running as root after an)72 +183.6 R/F2 10/Times-Italic@0 SF(su)2.507 E F0 5.007(.B)C .007 +(efore printing each primary prompt,)-5.007 F .305(Bash e)72 195.6 R +.305(xpands the v)-.15 F(ariable)-.25 E F1($PR)2.805 E(OMPT_COMMAND)-.3 +E F0 .305(and, if it has a v)2.805 F .306(alue, e)-.25 F -.15(xe)-.15 G +.306(cutes the e).15 F .306(xpanded v)-.15 F .306(alue as)-.25 F 3.735 +(ac)72 207.6 S 1.235(ommand, allo)-3.735 F 1.234 +(wing additional prompt customization.)-.25 F -.15(Fo)6.234 G 3.734(re) +.15 G 1.234(xample, this assignment causes the current)-3.884 F(user)72 +219.6 Q 2.917(,t)-.4 G .417 +(he current host, the time, the last component of the current w)-2.917 F +.417(orking directory)-.1 F 2.917(,t)-.65 G .418(he le)-2.917 F -.15(ve) +-.25 G 2.918(lo).15 G 2.918(fs)-2.918 G .418(hell nest-)-2.918 F(ing, a\ +nd the history number of the current command to be embedded into the pr\ +imary prompt:)72 231.6 Q/F3 10/Courier@0 SF 6($P)97 249.6 S +(S1='\\u@\\h [\\t] \\W\($SHLVL:\\!\)\\$ ')-6 E +(chet@odin [21:03:44] documentation\(2:636\)$ cd ..)97 261.6 Q +(chet@odin [21:03:54] src\(2:637\)$)97 273.6 Q F0 .146(The string being\ + assigned is surrounded by single quotes so that if it is e)72 295.2 R +.146(xported, the v)-.15 F .146(alue of)-.25 F F1($SHL)2.646 E(VL)-.92 E +F0(will)2.646 E(be updated by a child shell:)72 307.2 Q F3 +(chet@odin [21:17:35] src\(2:638\)$ export PS1)97 325.2 Q +(chet@odin [21:17:40] src\(2:639\)$ bash)97 337.2 Q +(chet@odin [21:17:46] src\(3:696\)$)97 349.2 Q F0 +(The \\$ escape is displayed as \231)72 370.8 Q F1($)A F0 2.5<9a77>C +(hen running as a normal user)-2.5 E 2.5(,b)-.4 G(ut as \231)-2.7 E F1 +(#)A F0 2.5<9a77>C(hen running as root.)-2.5 E F1 2.5(4.9. File)72 394.8 +R(System V)2.5 E(iews)-.37 E F0 .029(Since Berk)97 410.4 R(ele)-.1 E +2.529(yi)-.15 G .029 +(ntroduced symbolic links in 4.2 BSD, one of their most anno)-2.529 F +.03(ying properties has been)-.1 F .764(the \231w)72 422.4 R .764 +(arping\232 to a completely dif)-.1 F .764 +(ferent area of the \214le system when using)-.25 F F1(cd)3.263 E F0 +3.263(,a)C .763(nd the resultant non-intu-)-3.263 F(iti)72 434.4 Q .704 +-.15(ve b)-.25 H(eha).15 E .405(vior of \231)-.2 F F1 .405(cd ..)B F0 +2.905(\232. The)B/F4 9/Times-Roman@0 SF(UNIX)2.905 E F0 -.1(ke)2.905 G +.405(rnel treats symbolic links).1 F F2(physically)2.905 E F0 5.405(.W)C +.405(hen the k)-5.405 F .405(ernel is translating)-.1 F 3.223(ap)72 +446.4 S .723(athname in which one component is a symbolic link, it repl\ +aces all or part of the pathname while pro-)-3.223 F .668 +(cessing the link.)72 458.4 R .668 +(If the contents of the symbolic link be)5.668 F .669 +(gin with a slash, the k)-.15 F .669(ernel replaces the pathname)-.1 F +.219(entirely; if not, the link contents replace the current component.) +72 470.4 R .219(In either case, the symbolic link is visible.)5.219 F +.058(If the link v)72 482.4 R .058(alue is an absolute pathname, the us\ +er \214nds himself in a completely dif)-.25 F .059 +(ferent part of the \214le sys-)-.25 F(tem.)72 494.4 Q .704(Bash pro)97 +510 R .704(vides a)-.15 F F2(lo)3.203 E(gical)-.1 E F0(vie)3.203 E 3.203 +(wo)-.25 G 3.203(ft)-3.203 G .703(he \214le system.)-3.203 F .703 +(In this def)5.703 F .703(ault mode, command and \214lename com-)-.1 F +.522(pletion and b)72 522 R .522(uiltin commands such as)-.2 F F1(cd) +3.022 E F0(and)3.022 E F1(pushd)3.022 E F0 .522 +(which change the current w)3.022 F .522(orking directory transpar)-.1 F +(-)-.2 E .127(ently follo)72 534 R 2.627(ws)-.25 G .127 +(ymbolic links as if the)-2.627 F 2.627(yw)-.15 G .127(ere directories.) +-2.627 F(The)5.126 E F1($PWD)2.626 E F0 -.25(va)2.626 G .126 +(riable, which holds the shell').25 F 2.626(si)-.55 G .126(dea of)-2.626 +F .366(the current w)72 546 R .366(orking directory)-.1 F 2.866(,d)-.65 +G .367 +(epends on the path used to reach the directory rather than its ph) +-2.866 F .367(ysical loca-)-.05 F +(tion in the local \214le system hierarch)72 558 Q 3.8 -.65(y. F)-.05 H +(or e).5 E(xample:)-.15 E F3 6($c)97 576 S 6(d/)-6 G(usr/local/bin)-6 E +6($e)97 588 S(cho $PWD)-6 E(/usr/local/bin)97 600 Q 6($p)97 612 S(wd)-6 +E(/usr/local/bin)97 624 Q 6($/)97 636 S(bin/pwd)-6 E +(/net/share/sun4/local/bin)97 648 Q 6($c)97 660 S 6(d.)-6 G(.)-6 E 6($p) +97 672 S(wd)-6 E(/usr/local)97 684 Q 6($/)97 696 S(bin/pwd)-6 E +(/net/share/sun4/local)97 708 Q 6($c)97 720 S 6(d.)-6 G(.)-6 E EP +%%Page: 8 8 +%%BeginPageSetup +BP +%%EndPageSetup +/F0 10/Times-Roman@0 SF(-8-)282.17 48 Q/F1 10/Courier@0 SF 6($p)97 84 S +(wd)-6 E(/usr)97 96 Q 6($/)97 108 S(bin/pwd)-6 E(/usr)97 120 Q F0 .3(On\ +e problem with this, of course, arises when programs that do not unders\ +tand the shell')72 141.6 R 2.8(sl)-.55 G .3(ogical notion of)-2.8 F .217 +(the \214le system interpret \231..)72 153.6 R 2.718<9a64>-.7 G(if) +-2.718 E(ferently)-.25 E 5.218(.T)-.65 G .218 +(his generally happens when Bash completes \214lenames containing)-5.218 +F(\231..)72 165.6 Q 3.384<9a61>-.7 G .884 +(ccording to a logical hierarch)-3.384 F 3.384(yw)-.05 G .884 +(hich does not correspond to their ph)-3.384 F .883(ysical location.) +-.05 F -.15(Fo)5.883 G 3.383(ru).15 G .883(sers who)-3.383 F +(\214nd this troublesome, a corresponding)72 177.6 Q/F2 10 +/Times-Italic@0 SF(physical)2.5 E F0(vie)2.5 E 2.5(wo)-.25 G 2.5(ft)-2.5 +G(he \214le system is a)-2.5 E -.25(va)-.2 G(ilable:).25 E F1 6($c)97 +195.6 S 6(d/)-6 G(usr/local/bin)-6 E 6($p)97 207.6 S(wd)-6 E +(/usr/local/bin)97 219.6 Q 6($s)97 231.6 S(et -o physical)-6 E 6($p)97 +243.6 S(wd)-6 E(/net/share/sun4/local/bin)97 255.6 Q/F3 10/Times-Bold@0 +SF 2.5(4.10. Inter)72 285.6 R(nationalization)-.15 E F0 .145 +(One of the most signi\214cant impro)97 301.2 R -.15(ve)-.15 G .145 +(ments in v).15 F .145(ersion 1.13 of Bash w)-.15 F .145 +(as the change to \231eight-bit clean-)-.1 F 2.933(liness\232. Pre)72 +313.2 R .433(vious v)-.25 F .432 +(ersions used the eighth bit of characters to mark whether or not the) +-.15 F 2.932(yw)-.15 G .432(ere quoted when)-2.932 F 1.495(performing w) +72 325.2 R 1.495(ord e)-.1 F 3.995(xpansions. While)-.15 F 1.495 +(this did not af)3.995 F 1.496 +(fect the majority of users, most of whom used only)-.25 F(se)72 337.2 Q +-.15(ve)-.25 G 1.236(n-bit ASCII characters, some found it con\214ning.) +.15 F(Be)6.236 E 1.236(ginning with v)-.15 F 1.236 +(ersion 1.13, Bash implemented a)-.15 F(dif)72 349.2 Q .02(ferent quoti\ +ng mechanism that did not alter the eighth bit of characters.)-.25 F +.021(This allo)5.021 F .021(wed Bash to manipulate)-.25 F .427 +(\214les with \231odd\232 characters in their names, b)72 361.2 R .427 +(ut did nothing to help users enter those names, so v)-.2 F .426 +(ersion 1.13)-.15 F 1.458 +(introduced changes to readline that made it eight-bit clean as well.)72 +373.2 R 1.458(Options e)6.458 F 1.458(xist that force readline to)-.15 F +.744(attach no special signi\214cance to characters with the eighth bit\ + set \(the def)72 385.2 R .744(ault beha)-.1 F .744(vior is to con)-.2 F +-.15(ve)-.4 G .744(rt these).15 F .641(characters to meta-pre\214x)72 +397.2 R .641(ed k)-.15 F .941 -.15(ey s)-.1 H .642 +(equences\) and to output these characters without con).15 F -.15(ve)-.4 +G .642(rsion to meta-pre-).15 F<8c78>72 409.2 Q .008(ed sequences.)-.15 +F .007(These changes, along with the e)5.007 F .007(xpansion of k)-.15 F +-.15(ey)-.1 G .007(maps to a full eight bits, enable readline to).15 F +-.1(wo)72 421.2 S(rk with most of the ISO-8859 f).1 E +(amily of character sets, used by man)-.1 E 2.5(yE)-.15 G +(uropean countries.)-2.5 E F3 2.5(4.11. POSIX)72 445.2 R(Mode)2.5 E F0 +.584(Although Bash is intended to be POSIX.2 conformant, there are area\ +s in which the def)97 460.8 R .584(ault beha)-.1 F(vior)-.2 E .463 +(is not compatible with the standard.)72 472.8 R -.15(Fo)5.463 G 2.962 +(ru).15 G .462(sers who wish to operate in a strict POSIX.2 en)-2.962 F +.462(vironment, Bash)-.4 F .505(implements a)72 484.8 R F2 .505 +(POSIX mode)3.005 F F0 5.505(.W)C .505(hen this mode is acti)-5.505 F +-.15(ve)-.25 G 3.005(,B).15 G .505(ash modi\214es its def)-3.005 F .505 +(ault operation where it dif)-.1 F(fers)-.25 E .267 +(from POSIX.2 to match the standard.)72 496.8 R .266 +(POSIX mode is entered when Bash is started with the)5.267 F F3(-posix) +2.766 E F0(option.)2.766 E .149(This feature is also a)72 508.8 R -.25 +(va)-.2 G .149(ilable as an option to the).25 F F3(set)2.649 E F0 -.2 +(bu)2.649 G(iltin,).2 E F3 .149(set -o posix)2.649 F F0 5.149(.F)C .149 +(or compatibility with other GNU)-5.299 F(softw)72 520.8 Q 4.02(are tha\ +t attempts to be POSIX.2 compliant, Bash also enters POSIX mode if the \ +v)-.1 F(ariable)-.25 E F3($POSIXL)72 532.8 Q(Y_CORRECT)-.92 E F0 5.824 +(is set when Bash is started or assigned a v)8.324 F 5.825 +(alue during e)-.25 F -.15(xe)-.15 G(cution.).15 E F3($POSIX_PED)72 +544.8 Q(ANTIC)-.35 E F0 .27 +(is accepted as well, to be compatible with some older GNU utilities.) +2.77 F .27(When Bash is)5.27 F .506(started in POSIX mode, for e)72 +556.8 R .506(xample, it sources the \214le named by the v)-.15 F .507 +(alue of)-.25 F F3($ENV)3.007 E F0 .507(rather than the \231nor)3.007 F +(-)-.2 E(mal\232 startup \214les, and does not allo)72 568.8 Q 2.5(wr) +-.25 G(eserv)-2.5 E(ed w)-.15 E(ords to be aliased.)-.1 E F3 2.5(5. New) +72 592.8 R -.25(Fe)2.5 G(atur).25 E(es and Futur)-.18 E 2.5(eP)-.18 G +(lans)-2.5 E F0 1.632(There are se)97 608.4 R -.15(ve)-.25 G 1.632 +(ral features introduced in the current v).15 F 1.631(ersion of Bash, v) +-.15 F 1.631(ersion 1.14, and a number)-.15 F .241 +(under consideration for future releases.)72 620.4 R .242 +(This section will brie\215y detail the ne)5.242 F 2.742(wf)-.25 G .242 +(eatures in v)-2.742 F .242(ersion 1.14 and)-.15 F(describe se)72 632.4 +Q -.15(ve)-.25 G(ral features that may appear in later v).15 E(ersions.) +-.15 E F3 2.5(5.1. New)72 656.4 R -.25(Fe)2.5 G(atur).25 E +(es in Bash-1.14)-.18 E F0 .884(The ne)97 672 R 3.384(wf)-.25 G .884 +(eatures a)-3.384 F -.25(va)-.2 G .884(ilable in Bash-1.14 answer se).25 +F -.15(ve)-.25 G .883(ral of the most common requests for enhance-).15 F +2.931(ments. Most)72 684 R(notably)2.931 E 2.931(,t)-.65 G .432(here is\ + a mechanism for including non-visible character sequences in prompts, \ +such)-2.931 F .136 +(as those which cause a terminal to print characters in dif)72 696 R +.135(ferent colors or in standout mode.)-.25 F .135(There w)5.135 F .135 +(as noth-)-.1 F .558(ing pre)72 708 R -.15(ve)-.25 G .558 +(nting the use of these sequences in earlier v).15 F .559(ersions, b) +-.15 F .559(ut the readline redisplay algorithm assumed)-.2 F +(each character occupied ph)72 720 Q(ysical screen space and w)-.05 E +(ould wrap lines prematurely)-.1 E(.)-.65 E EP +%%Page: 9 9 +%%BeginPageSetup +BP +%%EndPageSetup +/F0 10/Times-Roman@0 SF(-9-)282.17 48 Q .13(Readline has a fe)97 84 R +2.63(wn)-.25 G .63 -.25(ew va)-2.63 H .13(riables, se).25 F -.15(ve)-.25 +G .13(ral ne).15 F 2.63(wb)-.25 G .13 +(indable commands, and some additional emacs mode)-2.63 F(def)72 96 Q +.918(ault k)-.1 F 1.218 -.15(ey b)-.1 H 3.418(indings. A).15 F(ne)3.418 +E 3.418(wh)-.25 G .919(istory search mode has been implemented: in this\ + mode, readline searches)-3.418 F .336(the history for lines be)72 108 R +.336(ginning with the characters between the be)-.15 F .336 +(ginning of the current line and the cursor)-.15 F(.)-.55 E .555(The e) +72 120 R .556(xisting readline incremental search commands no longer ma\ +tch identical lines more than once.)-.15 F(File-)5.556 E 1.979 +(name completion no)72 132 R 4.479(we)-.25 G 1.979(xpands v)-4.629 F +1.979(ariables in directory names.)-.25 F 1.978(The history e)6.978 F +1.978(xpansion f)-.15 F 1.978(acilities are no)-.1 F(w)-.25 E 1.449 +(nearly completely csh-compatible: missing modi\214ers ha)72 144 R 1.749 +-.15(ve b)-.2 H 1.449(een added and history substitution has been).15 F +-.15(ex)72 156 S(tended.).15 E(Se)97 171.6 Q -.15(ve)-.25 G .474 +(ral of the features described earlier).15 F 2.973(,s)-.4 G .473(uch as) +-2.973 F/F1 10/Times-Bold@0 SF .473(set -o posix)2.973 F F0(and)2.973 E +F1($POSIX_PED)2.973 E(ANTIC)-.35 E F0 2.973(,a)C .473(re ne)-2.973 F +2.973(wi)-.25 G(n)-2.973 E -.15(ve)72 183.6 S .106(rsion 1.14.).15 F +.106(There is a ne)5.106 F 2.606(ws)-.25 G .106(hell v)-2.606 F +(ariable,)-.25 E F1(OSTYPE)2.606 E F0 2.606(,t)C 2.606(ow)-2.606 G .106 +(hich Bash assigns a v)-2.606 F .106(alue that identi\214es the v)-.25 F +(er)-.15 E(-)-.2 E 1.38(sion of)72 195.6 R/F2 9/Times-Roman@0 SF(UNIX) +3.88 E F0(it')3.88 E 3.879(sr)-.55 G 1.379(unning on \(great for puttin\ +g architecture-speci\214c binary directories into the)-3.879 F F1($P) +3.879 E -.95(AT)-.74 G(H).95 E F0(\).)A -1 -.8(Tw o)72 207.6 T -.25(va) +6.215 G 2.915(riables ha).25 F 3.215 -.15(ve b)-.2 H 2.915(een renamed:) +.15 F F1($HISTCONTR)5.416 E(OL)-.3 E F0(replaces)5.416 E F1 +($history_contr)5.416 E(ol)-.18 E F0 5.416(,a)C(nd)-5.416 E F1 +($HOSTFILE)5.416 E F0(replaces)72 219.6 Q F1 +($hostname_completion_\214le)2.521 E F0 5.021(.I)C 2.521(nb)-5.021 G +.021(oth cases, the old names are accepted for backw)-2.521 F .02 +(ards compatibil-)-.1 F(ity)72 231.6 Q 5.788(.T)-.65 G .788(he ksh) +-5.788 F/F3 10/Times-Italic@0 SF(select)3.288 E F0 .788 +(construct, which allo)3.288 F .788 +(ws the generation of simple menus, has been implemented.)-.25 F(Ne) +5.788 E(w)-.25 E 1.496(capabilities ha)72 243.6 R 1.796 -.15(ve b)-.2 H +1.496(een added to e).15 F 1.495(xisting v)-.15 F(ariables:)-.25 E F1 +($auto_r)3.995 E(esume)-.18 E F0 1.495(can no)3.995 F 3.995(wt)-.25 G +(ak)-3.995 E 3.995(ev)-.1 G 1.495(alues of)-4.245 F F3 -.2(ex)3.995 G +(act).2 E F0(or)3.995 E F3(sub-)3.995 E(string)72 255.6 Q F0 4.843(,a)C +(nd)-4.843 E F1($HISTCONTR)4.843 E(OL)-.3 E F0 2.343(understands the v) +4.843 F(alue)-.25 E F3(ignor)4.844 E(eboth)-.37 E F0 4.844(,w)C 2.344 +(hich combines the tw)-4.844 F 4.844(op)-.1 G(re)-4.844 E(viously)-.25 E +1.556(acceptable v)72 267.6 R 4.056(alues. The)-.25 F F1(dirs)4.056 E F0 +-.2(bu)4.056 G 1.556(iltin has acquired options to print out speci\214c\ + members of the directory).2 F 3.062(stack. The)72 279.6 R F1($nolinks) +3.062 E F0 -.25(va)3.062 G .562(riable, which forces a ph).25 F .562 +(ysical vie)-.05 F 3.062(wo)-.25 G 3.062(ft)-3.062 G .563 +(he \214le system, has been superseded by the)-3.062 F F1<ad50>72 291.6 +Q F0 .494(option to the)2.994 F F1(set)2.994 E F0 -.2(bu)2.994 G .494 +(iltin \(equi).2 F -.25(va)-.25 G .494(lent to).25 F F1 .494(set -o ph) +2.994 F(ysical)-.15 E F0 .493(\); the v)B .493 +(ariable is retained for backw)-.25 F .493(ards compati-)-.1 F(bility)72 +303.6 Q 5.196(.T)-.65 G .196(he v)-5.196 F .196 +(ersion string contained in)-.15 F F1($B)2.696 E(ASH_VERSION)-.3 E F0 +(no)2.696 E 2.696(wi)-.25 G .196(ncludes an indication of the patch le) +-2.696 F -.15(ve)-.25 G 2.696(la).15 G(s)-2.696 E .85(well as the \231b) +72 315.6 R .85(uild v)-.2 F 3.35(ersion\232. Some)-.15 F .85 +(little-used features ha)3.35 F 1.15 -.15(ve b)-.2 H .85(een remo).15 F +-.15(ve)-.15 G 3.35(d: the).15 F F1(by)3.35 E(e)-.1 E F0(synon)3.35 E +.85(ym for)-.15 F F1(exit)3.35 E F0(and)3.35 E(the)72 327.6 Q F1($NO_PR) +3.498 E(OMPT_V)-.3 E(ARS)-1.35 E F0 -.25(va)3.498 G .998 +(riable are gone.).25 F .998(There is no)5.998 F 3.498(wa)-.25 G 3.498 +(no)-3.498 G -2.19 -.18(rg a)-3.498 H .998 +(nized test suite that can be run as a).18 F(re)72 339.6 Q +(gression test when b)-.15 E(uilding a ne)-.2 E 2.5(wv)-.25 G +(ersion of Bash.)-2.65 E 1.696(The documentation has been thoroughly o) +97 355.2 R -.15(ve)-.15 G 1.696(rhauled: there is a ne).15 F 4.196(wm) +-.25 G 1.695(anual page on the readline)-4.196 F .467(library and the)72 +367.2 R F3(info)2.967 E F0 .467 +(\214le has been updated to re\215ect the current v)2.967 F 2.968 +(ersion. As)-.15 F(al)2.968 E -.1(wa)-.1 G .468(ys, as man).1 F 2.968 +(yb)-.15 G .468(ugs as possi-)-3.168 F(ble ha)72 379.2 Q .3 -.15(ve b) +-.2 H(een \214x).15 E(ed, although some surely remain.)-.15 E F1 2.5 +(5.2. Other)72 403.2 R -.25(Fe)2.5 G(atur).25 E(es)-.18 E F0 1.68 +(There are a fe)97 418.8 R 4.18(wf)-.25 G 1.68 +(eatures that I hope to include in later Bash releases.)-4.18 F 1.68 +(Some are based on w)6.68 F(ork)-.1 E(already done in other shells.)72 +430.8 Q .958(In addition to simple v)97 446.4 R .959(ariables, a future\ + release of Bash will include one-dimensional arrays, using)-.25 F .206 +(the ksh implementation of arrays as a model.)72 458.4 R .205 +(Additions to the ksh syntax, such as)5.205 F F3(varname)2.705 E F0 .205 +(=\( ... \) to assign)B 2.587(al)72 470.4 S .087(ist of w)-2.587 F .088 +(ords directly to an array and a mechanism to allo)-.1 F 2.588(wt)-.25 G +(he)-2.588 E F1 -.18(re)2.588 G(ad).18 E F0 -.2(bu)2.588 G .088 +(iltin to read a list of v).2 F .088(alues directly)-.25 F .092 +(into an array)72 482.4 R 2.592(,w)-.65 G .092(ould be desirable.)-2.692 +F(Gi)5.092 E -.15(ve)-.25 G 2.592(nt).15 G .092(hose e)-2.592 F .092 +(xtensions, the ksh)-.15 F F1 .092(set \255A)2.592 F F0 .091 +(syntax may not be w)2.591 F .091(orth support-)-.1 F(ing \(the)72 494.4 +Q F1<ad41>2.5 E F0(option assigns a list of v)2.5 E(alues to an array) +-.25 E 2.5(,b)-.65 G(ut is a rather peculiar special case\).)-2.7 E .76 +(Some shells include a means of)97 510 R F3(pr)3.26 E -.1(og)-.45 G -.15 +(ra).1 G(mmable).15 E F0 -.1(wo)3.26 G .76 +(rd completion, where the user speci\214es on a per).1 F(-)-.2 E .163 +(command basis ho)72 522 R 2.663(wt)-.25 G .163(he ar)-2.663 F .163(gum\ +ents of the command are to be treated when completion is attempted: as \ +\214le-)-.18 F .194(names, hostnames, e)72 534 R -.15(xe)-.15 G .194 +(cutable \214les, and so on.).15 F .195 +(The other aspects of the current Bash implementation could)5.195 F .482 +(remain as-is; the e)72 546 R .482(xisting heuristics w)-.15 F .481 +(ould still be v)-.1 F 2.981(alid. Only)-.25 F .481 +(when completing the ar)2.981 F .481(guments to a simple)-.18 F +(command w)72 558 Q(ould the programmable completion be in ef)-.1 E +(fect.)-.25 E .479(It w)97 573.6 R .479(ould also be nice to gi)-.1 F +.779 -.15(ve t)-.25 H .479(he user \214ner).15 F .479 +(-grained control o)-.2 F -.15(ve)-.15 G 2.98(rw).15 G .48 +(hich commands are sa)-2.98 F -.15(ve)-.2 G 2.98(do).15 G .48(nto the) +-2.98 F 1.786(history list.)72 585.6 R 1.786(One proposal is for a v) +6.786 F 1.786(ariable, tentati)-.25 F -.15(ve)-.25 G 1.786(ly named).15 +F F1(HISTIGNORE)4.286 E F0 4.285(,w)C 1.785(hich w)-4.285 F 1.785 +(ould contain a)-.1 F .496(colon-separated list of commands.)72 597.6 R +.496(Lines be)5.496 F .496 +(ginning with these commands, after the restrictions of)-.15 F F1($HIST) +2.997 E(-)-.92 E(CONTR)72 609.6 Q(OL)-.3 E F0(ha)2.65 E .45 -.15(ve b) +-.2 H .15(een applied, w).15 F .15 +(ould not be placed onto the history list.)-.1 F .15 +(The shell pattern-matching capa-)5.15 F(bilities could also be a)72 +621.6 Q -.25(va)-.2 G(ilable when specifying the contents of).25 E F1 +($HISTIGNORE)2.5 E F0(.)A .729(One thing that ne)97 637.2 R .729 +(wer shells such as)-.25 F F1(wksh)3.229 E F0 .729(\(also kno)3.229 F +.729(wn as)-.25 F F1(dtksh)3.23 E F0 3.23(\)p)C(ro)-3.23 E .73 +(vide is a command to dynami-)-.15 F 1.189 +(cally load code implementing additional b)72 649.2 R 1.189 +(uiltin commands into a running shell.)-.2 F 1.188(This ne)6.188 F 3.688 +(wb)-.25 G 1.188(uiltin w)-3.888 F(ould)-.1 E(tak)72 661.2 Q 2.875(ea) +-.1 G 2.875(no)-2.875 G .375 +(bject \214le or shared library implementing the \231body\232 of the b) +-2.875 F .375(uiltin \()-.2 F F3(xxx_b)A(uiltin\(\))-.2 E F0 .375 +(for those f)2.875 F(amiliar)-.1 E .052 +(with Bash internals\) and a structure containing the name of the ne)72 +673.2 R 2.552(wc)-.25 G .051(ommand, the function to call when the) +-2.552 F(ne)72 685.2 Q 3.458(wb)-.25 G .958(uiltin is in)-3.658 F -.2 +(vo)-.4 G -.1(ke).2 G 3.458(d\().1 G .959 +(presumably de\214ned in the shared object speci\214ed as an ar)-3.458 F +.959(gument\), and the docu-)-.18 F 1.352 +(mentation to be printed by the)72 697.2 R F1(help)3.851 E F0 1.351 +(command \(possibly present in the shared object as well\).)3.851 F +1.351(It w)6.351 F(ould)-.1 E(manage the details of e)72 709.2 Q +(xtending the internal table of b)-.15 E(uiltins.)-.2 E EP +%%Page: 10 10 +%%BeginPageSetup +BP +%%EndPageSetup +/F0 10/Times-Roman@0 SF(-10-)279.67 48 Q 3.291(Af)97 84 S 1.291 -.25 +(ew o)-3.291 H .791(ther b).25 F .791(uiltins w)-.2 F .791 +(ould also be desirable: tw)-.1 F 3.291(oa)-.1 G .791(re the POSIX.2) +-3.291 F/F1 10/Times-Bold@0 SF(getconf)3.292 E F0 .792 +(command, which prints)3.292 F 1.412(the v)72 96 R 1.412 +(alues of system con\214guration v)-.25 F 1.411 +(ariables de\214ned by POSIX.2, and a)-.25 F F1(diso)3.911 E(wn)-.1 E F0 +-.2(bu)3.911 G 1.411(iltin, which causes a).2 F 1.347 +(shell running with job control acti)72 108 R 1.647 -.15(ve t)-.25 H +3.847<6f99>.15 G(for)-3.847 E 1.347 +(get about\232 one or more background jobs in its internal jobs)-.18 F +3.465(table. Using)72 120 R F1(getconf)3.465 E F0 3.465(,f)C .965(or e) +-3.465 F .965(xample, a user could retrie)-.15 F 1.264 -.15(ve a v)-.25 +H .964(alue for)-.1 F F1($P)3.464 E -.95(AT)-.74 G(H).95 E F0 .964 +(guaranteed to \214nd all of the)3.464 F .884 +(POSIX standard utilities, or \214nd out ho)72 132 R 3.385(wl)-.25 G +.885 +(ong \214lenames may be in the \214le system containing a speci\214ed) +-3.385 F(directory)72 144 Q(.)-.65 E 1.521 +(There are no implementation timetables for an)97 159.6 R 4.021(yo)-.15 +G 4.021(ft)-4.021 G 1.52(hese features, nor are there concrete plans to) +-4.021 F(include them.)72 171.6 Q(If an)5 E(yone has comments on these \ +proposals, feel free to send me electronic mail.)-.15 E F1 2.5 +(6. Re\215ections)72 195.6 R(and Lessons Lear)2.5 E(ned)-.15 E F0 .433 +(The lesson that has been repeated most often during Bash de)97 211.2 R +-.15(ve)-.25 G .433(lopment is that there are dark corners).15 F .181 +(in the Bourne shell, and people use all of them.)72 223.2 R .18 +(In the original description of the Bourne shell, quoting and)5.181 F +.073(the shell grammar are both poorly speci\214ed and incomplete; subs\ +equent descriptions ha)72 235.2 R .373 -.15(ve n)-.2 H .073 +(ot helped much.).15 F 1.856(The grammar presented in Bourne')72 247.2 R +4.356(sp)-.55 G 1.856(aper describing the shell distrib)-4.356 F 1.855 +(uted with the Se)-.2 F -.15(ve)-.25 G 1.855(nth Edition of).15 F/F2 9 +/Times-Roman@0 SF(UNIX)72 259.2 Q F0 2.5<8769>C 2.5(ss)-2.5 G 2.5(of) +-2.5 G(ar of)-2.6 E 2.5(ft)-.25 G(hat it does not allo)-2.5 E 2.5(wt) +-.25 G(he command)-2.5 E/F3 10/Courier@0 SF(who|wc)2.5 E F0 5(.I)C 2.5 +(nf)-5 G(act, as T)-2.6 E(om Duf)-.8 E 2.5(fs)-.25 G(tates:)-2.5 E 1.375 +(Nobody really kno)97 274.8 R 1.375(ws what the Bourne shell')-.25 F +3.875(sg)-.55 G 1.375(rammar is.)-3.875 F(Ev)6.376 E 1.376(en e)-.15 F +1.376(xamination of the source)-.15 F(code is little help.\210)97 286.8 +Q .382(The POSIX.2 standard includes a)72 302.4 R/F4 10/Times-Italic@0 +SF(yacc)2.882 E F0 .382 +(grammar that comes close to capturing the Bourne shell')2.882 F 2.882 +(sb)-.55 G(eha)-2.882 E(vior)-.2 E(,)-.4 E -.2(bu)72 314.4 S 3.246(ti).2 +G 3.246(td)-3.246 G(isallo)-3.246 E .747(ws some constructs which sh ac\ +cepts without complaint \255 and there are scripts out there that)-.25 F +.501(use them.)72 326.4 R .501(It took a fe)5.501 F 3.001(wv)-.25 G .501 +(ersions and se)-3.151 F -.15(ve)-.25 G .501(ral b).15 F .5 +(ug reports before Bash implemented sh-compatible quoting,)-.2 F .279 +(and there are still some \231le)72 338.4 R -.05(ga)-.15 G .279 +(l\232 sh constructs which Bash \215ags as syntax errors.).05 F .28 +(Complete sh compatibility)5.28 F(is a tough nut.)72 350.4 Q 1.231 +(The shell is bigger and slo)97 366 R 1.231(wer than I w)-.25 F 1.231 +(ould lik)-.1 F 1.23(e, though the current v)-.1 F 1.23 +(ersion is substantially f)-.15 F(aster)-.1 E .086(than pre)72 378 R +(viously)-.25 E 5.086(.T)-.65 G .087 +(he readline library could stand a substantial re)-5.086 F 2.587 +(write. A)-.25 F .087(hand-written parser to replace the)2.587 F +(current)72 390 Q F4(yacc)2.978 E F0 .478(-generated one w)B .477 +(ould probably result in a speedup, and w)-.1 F .477(ould solv)-.1 F +2.977(eo)-.15 G .477(ne glaring problem:)-2.977 F(the)5.477 E .384 +(shell could parse commands in \231$\(...\)\232 constructs as the)72 402 +R 2.884(ya)-.15 G .385 +(re entered, rather than reporting errors when the)-2.884 F +(construct is e)72 414 Q(xpanded.)-.15 E 1.064(As al)97 429.6 R -.1(wa) +-.1 G 1.064(ys, there is some chaf).1 F 3.564(ft)-.25 G 3.564(og)-3.564 +G 3.564(ow)-3.564 G 1.064(ith the wheat.)-3.564 F 1.063 +(Areas of duplicated functionality need to be)6.063 F .382(cleaned up.) +72 441.6 R .382(There are se)5.382 F -.15(ve)-.25 G .382 +(ral cases where Bash treats a v).15 F .382 +(ariable specially to enable functionality a)-.25 F -.25(va)-.2 G +(ilable).25 E .185(another w)72 453.6 R .185(ay \()-.1 F F1($notify)A F0 +(vs.)2.684 E F1 .184(set -o notify)5.184 F F0(and)2.684 E F1($nolinks) +2.684 E F0(vs.)2.684 E F1 .184(set -o ph)2.684 F(ysical)-.15 E F0 2.684 +(,f)C .184(or instance\); the special treatment)-2.684 F 3.421(of the v) +72 465.6 R 3.421(ariable name should probably be remo)-.25 F -.15(ve) +-.15 G 5.921(d. A).15 F(fe)5.921 E 5.921(wm)-.25 G 3.422 +(ore things could stand remo)-5.921 F -.25(va)-.15 G 3.422(l; the).25 F +F1($allo)72 477.6 Q(w_null_glob_expansion)-.1 E F0(and)4.112 E F1 +($glob_dot_\214lenames)4.112 E F0 -.25(va)4.111 G 1.611 +(riables are of particularly questionable v).25 F(alue.)-.25 E(The)72 +489.6 Q F1($[...])3.977 E F0 1.477(arithmetic e)3.977 F -.25(va)-.25 G +1.478(luation syntax is redundant no).25 F 3.978(wt)-.25 G 1.478 +(hat the POSIX-mandated)-3.978 F F1($\(\(...\)\))3.978 E F0 1.478 +(construct has)3.978 F .326(been implemented, and could be deleted.)72 +501.6 R .326(It w)5.326 F .326(ould be nice if the te)-.1 F .326 +(xt output by the)-.15 F F1(help)2.825 E F0 -.2(bu)2.825 G .325 +(iltin were e).2 F(xter)-.15 E(-)-.2 E .061 +(nal to the shell rather than compiled into it.)72 513.6 R .062 +(The beha)5.062 F .062(vior enabled by)-.2 F F1 +($command_oriented_history)2.562 E F0 2.562(,w)C(hich)-2.562 E 1.125 +(causes the shell to attempt to sa)72 525.6 R 1.424 -.15(ve a)-.2 H +1.124(ll lines of a multi-line command in a single history entry).15 F +3.624(,s)-.65 G 1.124(hould be)-3.624 F(made the def)72 537.6 Q +(ault and the v)-.1 E(ariable remo)-.25 E -.15(ve)-.15 G(d.).15 E F1 2.5 +(7. A)72 561.6 R -.1(va)-1 G(ilability).1 E F0 .047 +(As with all other GNU softw)97 577.2 R .047(are, Bash is a)-.1 F -.25 +(va)-.2 G .047(ilable for anon).25 F .047(ymous FTP from)-.15 F F4(pr) +2.547 E(ep.ai.mit.edu:/pub/gnu)-.37 E F0 1.05(and from other GNU softw) +72 589.2 R 1.05(are mirror sites.)-.1 F 1.049(The current v)6.049 F +1.049(ersion is in)-.15 F F4(bash-1.14.1.tar)3.549 E(.gz)-1.11 E F0 +1.049(in that directory)3.549 F(.)-.65 E(Use)72 601.2 Q F4(ar)5.965 E +-.15(ch)-.37 G(ie).15 E F0 3.465(to \214nd the nearest archi)5.965 F +3.766 -.15(ve s)-.25 H 5.966(ite. The).15 F 3.466(latest v)5.966 F 3.466 +(ersion is al)-.15 F -.1(wa)-.1 G 3.466(ys a).1 F -.25(va)-.2 G 3.466 +(ilable for FTP from).25 F F4(bash.CWR)72 613.2 Q -.25(U.)-.4 G +(Edu:/pub/dist.).25 E F0(Bash documentation is a)5 E -.25(va)-.2 G +(ilable for FTP from).25 E F4(bash.CWR)2.5 E -.25(U.)-.4 G +(Edu:/pub/bash.).25 E F0 1.169(The Free Softw)97 628.8 R 1.169(are F)-.1 +F 1.169(oundation sells tapes and CD-R)-.15 F 1.168 +(OMs containing Bash; send electronic mail to)-.4 F F3 +(gnu@prep.ai.mit.edu)72 640.8 Q F0(or call)2.5 E F3(+1-617-876-3296)2.5 +E F0(for more information.)2.5 E .694(Bash is also distrib)97 656.4 R +.694(uted with se)-.2 F -.15(ve)-.25 G .694(ral v).15 F .694(ersions of) +-.15 F F2(UNIX)3.194 E F0 .694(-compatible systems.)B .695 +(It is included as /bin/sh)5.694 F .948(and /bin/bash on se)72 668.4 R +-.15(ve)-.25 G .948(ral Linux distrib).15 F .948 +(utions \(more about the dif)-.2 F .948 +(ference in a moment\), and as contrib)-.25 F(uted)-.2 E .32 LW 144 +676.4 72 676.4 DL/F5 8/Times-Roman@0 SF .781 +(\207S. R. Bourne, \231UNIX T)72 688.2 R .781(ime-Sharing System:)-.28 F +.781(The UNIX Shell\232,)4.781 F/F6 8/Times-Italic@0 SF .78 +(Bell System T)2.78 F(ec)-.736 E .78(hnical J)-.12 F(ournal)-.2 E F5 +2.78(,5)C .78(7\(6\), July-)-2.78 F(August, 1978, pp. 1971-1990.)72 +698.2 Q<8854>72 710 Q .431(om Duf)-.64 F .431 +(f, \231Rc \255 A Shell for Plan 9 and)-.2 F/F7 7/Times-Roman@0 SF(UNIX) +2.432 E F5(systems\232,)2.432 E F6(Pr)2.432 E .432 +(oc. of the Summer 1990 EUUG Confer)-.36 F(ence)-.296 E F5 2.432(,L)C +(on-)-2.432 E(don, July)72 720 Q 2(,1)-.52 G(990, pp. 21-33.)-2 E EP +%%Page: 11 11 +%%BeginPageSetup +BP +%%EndPageSetup +/F0 10/Times-Roman@0 SF(-11-)279.67 48 Q(softw)72 84 Q(are in BSDI')-.1 +E 2.5(sB)-.55 G(SD/386* and FreeBSD.)-2.5 E .598(The Linux distrib)97 +99.6 R .598(ution deserv)-.2 F .598(es special mention.)-.15 F .598 +(There are tw)5.598 F 3.099(oc)-.1 G .599 +(on\214gurations included in the stan-)-3.099 F .733(dard Bash distrib) +72 111.6 R .732(ution: a \231normal\232 con\214guration, in which all o\ +f the standard features are included, and a)-.2 F .519(\231minimal\232 \ +con\214guration, which omits job control, aliases, history and command \ +line editing, the directory)72 123.6 R .886(stack and)72 135.6 R/F1 10 +/Times-Bold@0 SF(pushd/popd/dirs,)3.386 E F0 .886(process substitution,\ + prompt string special character decoding, and the)3.386 F/F2 10 +/Times-Italic@0 SF(select)3.385 E F0 3.368(construct. This)72 147.6 R +.868(minimal v)3.368 F .869 +(ersion is designed to be a drop-in replacement for the traditional)-.15 +F/F3 9/Times-Roman@0 SF(UNIX)3.369 E F0(/bin/sh,)3.369 E +(and is included as the Linux /bin/sh in se)72 159.6 Q -.15(ve)-.25 G +(ral packagings.).15 E F1 2.5(8. Conclusion)72 183.6 R F0 .8 +(Bash is a w)97 199.2 R(orth)-.1 E 3.3(ys)-.05 G .8(uccessor to sh.)-3.3 +F .8(It is suf)5.8 F .8(\214ciently portable to run on nearly e)-.25 F +-.15(ve)-.25 G .8(ry v).15 F .8(ersion of)-.15 F F3(UNIX)3.299 E F0 .31 +(from 4.3 BSD to SVR4.2, and se)72 211.2 R -.15(ve)-.25 G(ral).15 E F3 +(UNIX)2.81 E F0 -.1(wo)2.81 G(rkalik).1 E 2.81(es. It)-.1 F .311(is rob) +2.81 F .311(ust enough to replace sh on most of those)-.2 F 1.515 +(systems, and pro)72 223.2 R 1.515(vides more functionality)-.15 F 6.515 +(.I)-.65 G 4.015(th)-6.515 G 1.515(as se)-4.015 F -.15(ve)-.25 G 1.515 +(ral thousand re).15 F 1.515(gular users, and their feedback has)-.15 F +(helped to mak)72 235.2 Q 2.5(ei)-.1 G 2.5(ta)-2.5 G 2.5(sg)-2.5 G +(ood as it is today \255 a testament to the bene\214ts of free softw) +-2.5 E(are.)-.1 E .32 LW 144 708.2 72 708.2 DL/F4 8/Times-Roman@0 SF +(*BSD/386 is a trademark of Berk)72 720 Q(ele)-.08 E 2(yS)-.12 G(oftw)-2 +E(are Design, Inc.)-.08 E EP +%%Trailer +end +%%EOF |