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(ables may be used as operands, and the result of an e)72 530.4 R .222
(xpression may be assigned to a v)-.15 F 2.722(ariable. 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
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.292(idely used and quite popular)-2.792 F 1.499(for its interacti)72
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(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
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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
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(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
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(nted and standardized functionality in).15 F .674
(these areas, which Bash implements.)72 123.6 R(The)5.674 E/F1 10
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(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
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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
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3.298 G .798(iltin, v).2 F .798(ariable substring remo)-.25 F -.25(va)
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(Bash also implements the \231$\(...\)\232 command substitution syntax,\
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346.8 R .351(\231$\(...\)\232 construct e)2.851 F .351(xpands to the ou\
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(ut the \231$\(...\)\232 form is)-3.364 F(preferred because its quoting\
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(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-)
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(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($IFS)2.82 E F0 -.25(va)2.82 G .32(riable to split each w).25 F
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(xporting v)-.15 F .243(ariables in the shell')-.25 F 2.743(se)-.55 G
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5.882 F(tures can be found in the Bash documentation.)72 561.6 Q F1 2.5
(4.1. Startup)72 585.6 R(Files)2.5 E F0 .161(Bash e)97 601.2 R -.15(xe)
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(ferently than other shells.)-.25 F .162(The Bash beha)5.161 F .162
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(the csh principle of startup \214les with \214x)72 613.2 R .29
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(cuted for each shell and the sh \231minimalist\232 beha).15 F(vior)-.2
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(ar)-2.996 E .496(ge a \214le created by a child process can gro)-.18 F
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(ype export)-6 E(export is a shell builtin)97 297.6 Q 6($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
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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)
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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\
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626.4 S 3.56(nb).25 G 1.06(indable commands and program-speci\214c k)
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(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
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(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 \(a).15 F(meta-pre\214x)72 678 Q .082
(ed k)-.15 F .382 -.15(ey s)-.1 H .081(equence consists of the characte\
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(e\214x)-.37 E F0(character)72 690 Q 3.233(,u)-.4 G .733
(sually escape, which selects an alternate k)-3.233 F -.15(ey)-.1 G .734
(map\), 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)
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2.785(wv)-.25 G(ariables)-3.035 E .12(or k)72 111.6 R .42 -.15(ey b)-.1
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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
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("\\C-xp": "PATH=${PATH}\\e\\C-e\\C-a\\ef\\C-f")97 189.6 Q 6(#p)97 201.6
S(repare to type a quoted word -- insert open and close double)-6 E 6
(#q)97 213.6 S(uotes and move to just after the open quote)-6 E
("\\C-x\\"": "\\"\\"\\C-b")97 225.6 Q 6(#Q)97 237.6 S
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249.6 Q($endif)97 261.6 Q F0 .322(There is a readline command to re-rea\
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 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
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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)
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(If there is only one possible completion, the rest of the)5.523 F .358
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(hooks so that applications can pro)72 470.4 R .482
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(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
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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\
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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)
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(iltins to manipulate the history list.).2 F .391(The v)5.391 F .391
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(cution, with optional editing, of commands from the history list.).15 F
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(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)
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(ay the shell treats simple command names: if job control is acti)-.1 F
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(ariable is set, sin-)-.25 F(gle-w)72 373.2 Q .239(ord simple commands \
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(wp)-.25 G(rocess.)-2.5 E F2 2.5(4.6. Brace)72 409.2 R(Expansion)2.5 E
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(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
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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
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(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\
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.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
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(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\
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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
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E .729(can be put into the prompt \(e.g.,)72 135.6 R F1($SHL)3.228 E(VL)
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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
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(he current host, the time, the last component of the current w)-2.917 F
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(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\
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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($)A F0 2.5<9a77>C
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(ntroduced symbolic links in 4.2 BSD, one of their most anno)-2.529 F
.03(ying properties has been)-.1 F .764(the \231w)72 422.4 R .764
(arping\232 to a completely dif)-.1 F .764
(ferent area of the \214le system when using)-.25 F F1(cd)3.263 E F0
3.263(,a)C .763(nd the resultant non-intu-)-3.263 F(iti)72 434.4 Q .704
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2.905(\232. The)B/F4 9/Times-Roman@0 SF(UNIX)2.905 E F0 -.1(ke)2.905 G
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(cessing the link.)72 458.4 R .668
(If the contents of the symbolic link be)5.668 F .669
(gin with a slash, the k)-.15 F .669(ernel replaces the pathname)-.1 F
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.058(If the link v)72 482.4 R .058(alue is an absolute pathname, the us\
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510 R .704(vides a)-.15 F F2(lo)3.203 E(gical)-.1 E F0(vie)3.203 E 3.203
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(-)-.2 E .127(ently follo)72 534 R 2.627(ws)-.25 G .127
(ymbolic links as if the)-2.627 F 2.627(yw)-.15 G .127(ere directories.)
-2.627 F(The)5.126 E F1($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($c)97 720 S 6(d.)-6 G(.)-6 E EP
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/F0 10/Times-Roman@0 SF(-8-)282.17 48 Q/F1 10/Courier@0 SF 6($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
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/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
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/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\
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(ot helped much.).15 F 1.856(The grammar presented in Bourne')72 247.2 R
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(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
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.501(use them.)72 326.4 R .501(It took a fe)5.501 F 3.001(wv)-.25 G .501
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(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
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(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
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(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)
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(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($notify)A F0
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F1($allo)72 477.6 Q(w_null_glob_expansion)-.1 E F0(and)4.112 E F1
($glob_dot_\214lenames)4.112 E F0 -.25(va)4.111 G 1.611
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489.6 Q F1($[...])3.977 E F0 1.477(arithmetic e)3.977 F -.25(va)-.25 G
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(hat the POSIX-mandated)-3.978 F F1($\(\(...\)\))3.978 E F0 1.478
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501.6 R .326(It w)5.326 F .326(ould be nice if the te)-.1 F .326
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(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
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(causes the shell to attempt to sa)72 525.6 R 1.424 -.15(ve a)-.2 H
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3.624(,s)-.65 G 1.124(hould be)-3.624 F(made the def)72 537.6 Q
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(As with all other GNU softw)97 577.2 R .047(are, Bash is a)-.1 F -.25
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3.766 -.15(ve s)-.25 H 5.966(ite. The).15 F 3.466(latest v)5.966 F 3.466
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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
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(\207S. R. Bourne, \231UNIX T)72 688.2 R .781(ime-Sharing System:)-.28 F
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(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
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E 2.5(sB)-.55 G(SD/386* and FreeBSD.)-2.5 E .598(The Linux distrib)97
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72 111.6 R .732(ution: a \231normal\232 con\214guration, in which all o\
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(Bash is a w)97 199.2 R(orth)-.1 E 3.3(ys)-.05 G .8(uccessor to sh.)-3.3
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(*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
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