of features unique to bash.)108 261 R(Finally)108 273 Q 3.178(,s)-.65 G .678(ome of the changes and ne)145.258 273 R 3.178(wf)-.25 G .678(eatures to appear in the ne)268.486 273 R .678(xt bash release will be)-.15 F(discussed.)108 285 Q/F3 10/Times-Bold@0 SF 2.5(1. 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These)-.15 F(ne)2.519 E 2.519(wc)-.25 G(ommands)465.11 591 Q(ha)72 603 Q.395 -.15(ve t)-.2 H .095(he same status as system commands in directories lik).15 F(e)-.1 E F3(/bin)2.595 E F2 2.595(,a)C(llo)342.575 603 Q .096(wing users or groups to establish cus-)-.25 F(tom en)72 615 Q(vironments.)-.4E F3 2.5(2.1. 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Operators)-.18 F .524(to redirect input and)3.024 F(output may appear an)72 199.2 Q(ywhere in a simple command.)-.15 E(Some e)5 E(xamples are:)-.15 E/F3 10/Courier@0 SF(who)97 211.2 Q(trn -e -S1 -N)97 223.2 Q(ls -l /bin > binfiles)97235.2 Q(make > make.out 2>make.errs)97 247.2 Q F0 2.518(Ap)97 262.8 S .018(ipeline is a sequence of tw)111.738 262.8 R 2.518(oo)-.1 G 2.518(rm)230.056262.8 S .018(ore commands separated by the character)243.684 262.8 R/F4 10/Symbol SF<ef>2.519 E F0 5.019(.T)C .019(he standard output)430.082 262.8 R(of the \214rst command is connected to the standard input of the second.)72274.8 Q(Examples of pipelines include:)5 E F3(who | wc -l)97 286.8 Q(ls -l | sort +3nr)97 298.8 Q F0 .578(Simple commands and pipelines may be combined into)97 314.4 R F2(lists)3.078 EF0 5.578(.A)C .578(list is a sequence of pipelines sepa-)360.002 314.4 R .289(rated by one of)72 326.4 R F1(;)2.789 E F0(,)A F1(&)2.789 E F0(,)A F1(&&)2.789E F0 2.789(,o)C(r)185.103 326.4 Q F4<efef>2.789 E F0 2.789(,a)C .289(nd optionally terminated by)210.831 326.4 R F1(;)2.789 E F0(,)A F1(&)2.789 EF0 2.789(,o)C 2.789(ran)352.555 326.4 S -.25(ew)370.903 326.4 S 2.789(line. 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Some)-.1 F -.15(ex)2.5 G(amples are:).15 E F3(who ; date)97 386.4 Q(cd /usr/src || exit 1)97 398.4 Q(cd "$@" && xtitle $HOST: $PWD)97 410.4 Q F01.36(The shell programming language pro)97 426 R 1.361(vides a v)-.15 F 1.361(ariety of \215o)-.25 F 3.861(wc)-.25 G 1.361(ontrol structures.)353.276 426 R(The)6.361 E F1 -.25(fo)3.861 G(r).25 E F0(command)3.861 E(allo)72 438 Q .654(ws a list of commands to be e)-.25 F -.15(xe)-.15 G .654(cuted once for each w).15 F .654(ord in a w)-.1 F .654(ord list.)-.1 F(The)5.654 E F1(case)3.154 E F0 .654(command allo)3.154 F .654(ws a)-.25 F .627(list to be e)72 450 R -.15(xe)-.15 G .628(cuted if a w).15 F .628(ord matches a speci\214ed pattern.)-.1 F(The)5.628 E F1(while)3.128 E F0(and)3.128 E F1(until)3.128 E F0 .628(commands e)3.128 F -.15(xe)-.15 G .628(cute a list of).15 F 1.559(commands as long as a guard command completes successfully or f)72 462 R 1.559(ails, respecti)-.1 F -.15(ve)-.25 G(ly).15 E 6.559(.T)-.65 G(he)440.892 462 QF1(if)4.059 E F0(command)4.059 E(allo)72 474 Q(ws e)-.25 E -.15(xe)-.15 G(cution of dif).15 E(ferent command lists depending on the e)-.25 E(xit status of a guard command.)-.15 E(A)97 489.6 Q F2 .385(shell function)2.885 F F0 .385(associates a list of commands with a name.)2.885 F .386(Each time the name is used as a simple)5.385 F .938(command, the list is e)72501.6 R -.15(xe)-.15 G 3.438(cuted. 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Functions)72 513.6 R(may ha)2.5 E .3 -.15(ve t)-.2 H(heir o).15 E(wn ar)-.25 E(gument lists and local v)-.18 E(ariables, and may be recursi)-.25E -.15(ve)-.25 G(.).15 E .722(The shell language pro)97 529.2 R .722(vides v)-.15 F .722(ariables, which may be both set and referenced.)-.25 F 3.222(An)5.722 G .722(umber of special)435.906 529.2 R 1.02(parameters are present, such as)72 541.2 R F1($@)3.519 E F0 3.519(,w)C 1.019(hich returns the shell')231.257 541.2 R 3.519(sp)-.55 G 1.019(ositional parameters \(command-line ar)333.103 541.2 R(gu-)-.18 E(ments\),)72553.2 Q F1($?)2.906 E F0 2.906(,t)C .406(he e)122.812 553.2 R .406(xit status of the pre)-.15 F .406(vious command, and)-.25 F F1($$)2.906 E F02.906(,t)C .406(he shell')322.436 553.2 R 2.906(sp)-.55 G .406(rocess I.D.)368.248 553.2 R .407(In addition to pro)5.406 F(vid-)-.15 E .129(ing special parameters and user)72 565.2 R .129(-de\214ned v)-.2 F .129(ariables, the shell permits the v)-.25 F .128(alues of certain v)-.25 F .128(ariables to control)-.25 F .16(its beha)72 577.2 R(vior)-.2 E 5.16(.S)-.55 G.16(ome of these v)131.57 577.2 R .16(ariables include)-.25 F F1(IFS)2.661 E F02.661(,w)C .161(hich controls ho)284.202 577.2 R 2.661(wt)-.25 G .161(he shell splits w)361.375 577.2 R(ords,)-.1 E F1 -.74(PA)2.661 G(TH)-.21 E F02.661(,w)C(hich)486.78 577.2 Q .392(tells the shell where to look for commands, and)72 589.2 R F1(PS1)2.892 E F02.892(,w)C .392(hose v)297.01 589.2 R .392(alue is the string the shell uses to prompt for)-.25 F 3.371(commands. 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F).25 F 1.388(or e)-.15 F 1.388(xample, there are)-.15 F(${)72676.8 Q F2(name)A F0<3aad>A F2(wor)A(d)-.37 E F0 .891(}, which e)B .891(xpands to)-.15 F F2(wor)3.391 E(d)-.37 E F0(if)3.391 E F2(name)3.391 E F0 .891(is unset or null, and the in)3.391 F -.15(ve)-.4 G .89(rse ${).15 F F2(name)AF0(:+)A F2(wor)A(d)-.37 E F0 .89(}, which)B -.15(ex)72 688.8 S 1.203(pands to).15 F F2(wor)3.703 E(d)-.37 E F0(if)3.703 E F2(name)3.703 E F0 1.203(is set and not null.)3.703 F F2 1.203(Command substitution)6.203 F F0(allo)3.703 E 1.204(ws the output of a command to)-.25 F .918(replace the command name.)72 700.8 R .918(The syntax is `)5.918 F F2(command)AF0(`.)A F2(Command)5.918 E F0 .918(is e)3.418 F -.15(xe)-.15 G .918(cuted and it and the backquotes).15 F .299(are replaced by its output, with trailing ne)72 712.8 R .299(wlines remo)-.25F -.15(ve)-.15 G(d.).15 E F2 -.8(Pa)5.299 G .299(thname e).8 F(xpansion)-.2 EF0 .299(is a w)2.799 F .299(ay to e)-.1 F .299(xpand a w)-.15 F(ord)-.1 E 1.586(to a set of \214lenames.)72 724.8 R -.8(Wo)6.586 G 1.586(rds are re).8 F -.05(ga)-.15 G 1.586(rded as patterns, in which the characters).05 F F1(*)4.086 EF0(,)A F1(?)4.086 E F0 4.085(,a)C(nd)432.115 724.8 Q F1([)4.085 E F0(ha)4.085 E1.885 -.15(ve s)-.2 H(pecial).15 E EP%%Page: 3 3%%BeginPageSetupBP%%EndPageSetup/F0 10/Times-Roman@0 SF 2.5(-3-)279.67 48 S 2.845(meaning. 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