.\" $MirOS: src/bin/mksh/lksh.1,v 1.20 2016/11/11 23:31:35 tg Exp $ .\"- .\" Copyright (c) 2008, 2009, 2010, 2012, 2013, 2015, 2016 .\" mirabilos .\" .\" Provided that these terms and disclaimer and all copyright notices .\" are retained or reproduced in an accompanying document, permission .\" is granted to deal in this work without restriction, including un‐ .\" limited rights to use, publicly perform, distribute, sell, modify, .\" merge, give away, or sublicence. .\" .\" This work is provided “AS IS” and WITHOUT WARRANTY of any kind, to .\" the utmost extent permitted by applicable law, neither express nor .\" implied; without malicious intent or gross negligence. In no event .\" may a licensor, author or contributor be held liable for indirect, .\" direct, other damage, loss, or other issues arising in any way out .\" of dealing in the work, even if advised of the possibility of such .\" damage or existence of a defect, except proven that it results out .\" of said person’s immediate fault when using the work as intended. .\"- .\" Try to make GNU groff and AT&T nroff more compatible .\" * ` generates ‘ in gnroff, so use \` .\" * ' generates ’ in gnroff, \' generates ´, so use \*(aq .\" * - generates ‐ in gnroff, \- generates −, so .tr it to - .\" thus use - for hyphens and \- for minus signs and option dashes .\" * ~ is size-reduced and placed atop in groff, so use \*(TI .\" * ^ is size-reduced and placed atop in groff, so use \*(ha .\" * \(en does not work in nroff, so use \*(en .\" * <>| are problematic, so redefine and use \*(Lt\*(Gt\*(Ba .\" Also make sure to use \& *before* a punctuation char that is to not .\" be interpreted as punctuation, and especially with two-letter words .\" but also (after) a period that does not end a sentence (“e.g.\&”). .\" The section after the "doc" macropackage has been loaded contains .\" additional code to convene between the UCB mdoc macropackage (and .\" its variant as BSD mdoc in groff) and the GNU mdoc macropackage. .\" .ie \n(.g \{\ . if \*[.T]ascii .tr \-\N'45' . if \*[.T]latin1 .tr \-\N'45' . if \*[.T]utf8 .tr \-\N'45' . ds <= \[<=] . ds >= \[>=] . ds Rq \[rq] . ds Lq \[lq] . ds sL \(aq . ds sR \(aq . if \*[.T]utf8 .ds sL ` . if \*[.T]ps .ds sL ` . if \*[.T]utf8 .ds sR ' . if \*[.T]ps .ds sR ' . ds aq \(aq . ds TI \(ti . ds ha \(ha . ds en \(en .\} .el \{\ . ds aq ' . ds TI ~ . ds ha ^ . ds en \(em .\} .\" .\" Implement .Dd with the Mdocdate RCS keyword .\" .rn Dd xD .de Dd .ie \\$1$Mdocdate: \{\ . xD \\$2 \\$3, \\$4 .\} .el .xD \\$1 \\$2 \\$3 \\$4 \\$5 \\$6 \\$7 \\$8 .. .\" .\" .Dd must come before definition of .Mx, because when called .\" with -mandoc, it might implement .Mx itself, but we want to .\" use our own definition. And .Dd must come *first*, always. .\" .Dd $Mdocdate: November 11 2016 $ .\" .\" Check which macro package we use, and do other -mdoc setup. .\" .ie \n(.g \{\ . if \*[.T]utf8 .tr \[la]\*(Lt . if \*[.T]utf8 .tr \[ra]\*(Gt . ie d volume-ds-1 .ds tT gnu . el .ds tT bsd .\} .el .ds tT ucb .\" .\" Implement .Mx (MirBSD) .\" .ie "\*(tT"gnu" \{\ . eo . de Mx . nr curr-font \n[.f] . nr curr-size \n[.ps] . ds str-Mx \f[\n[curr-font]]\s[\n[curr-size]u] . ds str-Mx1 \*[Tn-font-size]\%MirOS\*[str-Mx] . if !\n[arg-limit] \ . if \n[.$] \{\ . ds macro-name Mx . parse-args \$@ . \} . if (\n[arg-limit] > \n[arg-ptr]) \{\ . nr arg-ptr +1 . ie (\n[type\n[arg-ptr]] == 2) \ . as str-Mx1 \~\*[arg\n[arg-ptr]] . el \ . nr arg-ptr -1 . \} . ds arg\n[arg-ptr] "\*[str-Mx1] . nr type\n[arg-ptr] 2 . ds space\n[arg-ptr] "\*[space] . nr num-args (\n[arg-limit] - \n[arg-ptr]) . nr arg-limit \n[arg-ptr] . if \n[num-args] \ . parse-space-vector . print-recursive .. . ec . ds sP \s0 . ds tN \*[Tn-font-size] .\} .el \{\ . de Mx . nr cF \\n(.f . nr cZ \\n(.s . ds aa \&\f\\n(cF\s\\n(cZ . if \\n(aC==0 \{\ . ie \\n(.$==0 \&MirOS\\*(aa . el .aV \\$1 \\$2 \\$3 \\$4 \\$5 \\$6 \\$7 \\$8 \\$9 . \} . if \\n(aC>\\n(aP \{\ . nr aP \\n(aP+1 . ie \\n(C\\n(aP==2 \{\ . as b1 \&MirOS\ #\&\\*(A\\n(aP\\*(aa . ie \\n(aC>\\n(aP \{\ . nr aP \\n(aP+1 . nR . \} . el .aZ . \} . el \{\ . as b1 \&MirOS\\*(aa . nR . \} . \} .. .\} .\"- .Dt LKSH 1 .Os MirBSD .Sh NAME .Nm lksh .Nd Legacy Korn shell built on mksh .Sh SYNOPSIS .Nm .Bk -words .Op Fl +abCefhiklmnprUuvXx .Op Fl +o Ar opt .Oo .Fl c Ar string \*(Ba .Fl s \*(Ba .Ar file .Op Ar args ... .Oc .Ek .Sh DESCRIPTION .Nm is a command interpreter intended exclusively for running legacy shell scripts. It is built on .Nm mksh ; refer to its manual page for details on the scripting language. It is recommended to port scripts to .Nm mksh instead of relying on legacy or idiotic POSIX-mandated behaviour, since the MirBSD Korn Shell scripting language is much more consistent. .Pp Note that it's strongly recommended to invoke .Nm with at least the .Fl o Ic posix option, if not both that .Em and Fl o Ic sh , to fully enjoy better compatibility to the .Tn POSIX standard (which is probably why you use .Nm over .Nm mksh in the first place) or legacy scripts, respectively. .Sh LEGACY MODE .Nm currently has the following differences from .Nm mksh : .Bl -bullet .It .\"XXX TODO: remove (some systems may wish to have lksh as ksh) There is no explicit support for interactive use, nor any command line editing or history code. Hence, .Nm is not suitable as a user's login shell, either; use .Nm mksh instead. .It The .Ev KSH_VERSION string identifies .Nm as .Dq Li LEGACY KSH instead of .Dq Li MIRBSD KSH . Note that the rest of the version string is identical between the two shell flavours, and the behaviour and differences can change between versions; see the accompanying manual page .Xr mksh 1 for the versions this document applies to. .It .Nm uses .Tn POSIX arithmetic, which has quite a few implications: The data type for arithmetic operations is the host .Tn ISO C .Vt long data type. Signed integer wraparound is Undefined Behaviour; this means that... .Bd -literal -offset indent $ echo $((2147483647 + 1)) .Ed .Pp \&... is permitted to, e.g. delete all files on your system (the figure differs for non-32-bit systems, the rule doesn't). The sign of the result of a modulo operation with at least one negative operand is unspecified. Shift operations on negative numbers are unspecified. Division of the largest negative number by \-1 is Undefined Behaviour. The compiler is permitted to delete all data and crash the system if Undefined Behaviour occurs (see above for an example). .It .\"XXX TODO: move this to FPOSIX The rotation arithmetic operators are not available. .It The shift arithmetic operators take all bits of the second operand into account; if they exceed permitted precision, the result is unspecified. .It .\"XXX TODO: move this to FPOSIX The .Tn GNU .Nm bash extension &\*(Gt to redirect stdout and stderr in one go is not parsed. .It .\"XXX TODO: drop along with allowing interactivity The .Nm mksh command line option .Fl T is not available. .It Unless .Ic set -o posix is active, .Nm always uses traditional mode for constructs like: .Bd -literal -offset indent $ set -- $(getopt ab:c "$@") $ echo $? .Ed .Pp POSIX mandates this to show 0, but traditional mode passes through the errorlevel from the .Xr getopt 1 command. .It .\"XXX TODO: move to FPOSIX/FSH Unlike .At .Nm ksh , .Nm mksh in .Fl o Ic posix or .Fl o Ic sh mode and .Nm lksh do not keep file descriptors \*(Gt 2 private from sub-processes. .It Functions defined with the .Ic function reserved word share the shell options .Pq Ic set -o instead of locally scoping them. .El .Sh SEE ALSO .Xr mksh 1 .Pp .Pa https://www.mirbsd.org/mksh.htm .Pp .Pa https://www.mirbsd.org/ksh\-chan.htm .Sh CAVEATS The distinction between the shell variants .Pq Nm lksh / Nm mksh and shell flags .Pq Fl o Ic posix / Ic sh will be reworked for an upcoming release. .Pp To use .Nm as .Pa /bin/sh , compilation to enable .Ic set -o posix by default if called as .Nm sh is highly recommended for better standards compliance. For better compatibility with legacy scripts, such as many .Tn Debian maintainer scripts, Upstart and SYSV init scripts, and other unfixed scripts, using the compile-time options for enabling .Em both .Ic set -o posix -o sh when the shell is run as .Nm sh is recommended. .Pp .Nm tries to make a cross between a legacy bourne/posix compatibl-ish shell and a legacy pdksh-alike but .Dq legacy is not exactly specified. .Pp The .Ic set built-in command does not currently have all options one would expect from a full-blown .Nm mksh or .Nm pdksh . .Pp Talk to the .Mx development team using the mailing list at .Aq miros\-mksh@mirbsd.org or the .Li \&#\&!/bin/mksh .Pq or Li \&#ksh IRC channel at .Pa irc.freenode.net .Pq Port 6697 SSL, 6667 unencrypted if you need any further quirks or assistance, and consider migrating your legacy scripts to work with .Nm mksh instead of requiring .Nm .