lksh(1) [centos man page]
LKSH(1) BSD General Commands Manual LKSH(1) NAME
lksh -- Legacy Korn shell built on mksh SYNOPSIS
lksh [-+abCefhiklmnprUuvXx] [-+o opt] [-c string | -s | file [args ...]] DESCRIPTION
lksh is a command interpreter intended exclusively for running legacy shell scripts. It is built on mksh; refer to its manual page for details on the scripting language. It is recommended to port scripts to mksh instead of relying on legacy or idiotic POSIX-mandated behav- iour, since the MirBSD Korn Shell scripting language is much more consistent. LEGACY MODE
lksh has the following differences from mksh: o lksh is not suitable for use as /bin/sh. o There is no explicit support for interactive use, nor any command line editing or history code. Hence, lksh is not suitable as a user's login shell, either; use mksh instead. o The KSH_VERSION string identifies lksh as ``LEGACY KSH'' instead of ``MIRBSD KSH''. o lksh only offers the traditional ten file descriptors to scripts. o lksh uses POSIX arithmetics, which has quite a few implications: The data type for arithmetics is the host ISO C long data type. Signed integer wraparound is Undefined Behaviour. The sign of the result of a modulo operation with at least one negative operand is unspeci- fied. 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. o The rotation arithmetic operators are not available. o The shift arithmetic operators take all bits of the second operand into account; if they exceed permitted precision, the result is unspecified. o The GNU bash extension &> to redirect stdout and stderr in one go is not parsed. o The mksh command line option -T is not available. o Unless set -o posix is active, lksh always uses traditional mode for constructs like: $ set -- $(getopt ab:c "$@") $ echo $? POSIX mandates this to show 0, but traditional mode passes through the errorlevel from the getopt(1) command. o lksh, unlike AT&T UNIX ksh, does not keep file descriptors > 2 private. SEE ALSO
mksh(1) https://www.mirbsd.org/mksh.htm https://www.mirbsd.org/ksh-chan.htm CAVEATS
lksh tries to make a cross between a legacy bourne/posix compatibl-ish shell and a legacy pdksh-alike but ``legacy'' is not exactly speci- fied. The set built-in command does not have all options one would expect from a full-blown mksh or pdksh. Talk to the MirOS development team using the mailing list at <miros-mksh@mirbsd.org> or the #!/bin/mksh (or #ksh) IRC channel at irc.freenode.net (Port 6697 SSL, 6667 unencrypted) if you need any further quirks or assistance, and consider migrating your legacy scripts to work with mksh instead of requiring lksh. MirBSD May 2, 2013 MirBSD
Check Out this Related Man Page
sh(1) General Commands Manual sh(1) NAME
sh - overview of various system shells SYNOPSIS
POSIX Shell option] ... string] [arg ...] option] ... string] [arg ...] Korn Shell option] ... string] [arg ...] option] ... string] [arg ...] C Shell [command_file] [argument_list ...] Key Shell DESCRIPTION
Remarks The POSIX .2 standard requires that, on a POSIX-compliant system, executing the command activates the POSIX shell (located in file on HP-UX systems), and executing the command produces an on-line manual entry that displays the syntax of the POSIX shell command-line. However, the command has historically been associated with the conventional Bourne shell, which could confuse some users. To meet stan- dards requirements and also clarify the relationships of the various shells and where they reside on the system, this entry provides com- mand-line syntax and a brief description of each shell, and lists the names of the manual entries where each shell is described in greater detail. The Bourne shell is removed from the system starting with HP-UX 11i Version 1.5. Please use the POSIX shell as an alternative. Shell Descriptions The HP-UX operating system supports the following shells: POSIX-conforming command programming language and command interpreter residing in file Can execute commands read from a terminal or a file. This shell conforms to current POSIX standards in effect at the time the HP-UX system release was introduced, and is similar to the Korn shell in many respects. Similar in many respects to the Korn shell, the POSIX shell contains a history mechanism, supports job control, and provides various other useful features. Korn-shell command programming language and commands interpreter residing in file Can execute commands read from a terminal or a file. This shell, like the POSIX shell, contains a his- tory mechanism, supports job control, and provides various other useful features. A command language interpreter that incorporates a command history buffer, C-language-like syntax, and job control facilities. Restricted version of the POSIX shell command interpreter. Sets up a login name and execution environment whose capabilities are more controlled (restricted) than normal user shells. restricted version of the Korn-shell command interpreter Sets up a login name and execution environment whose capabilities are more controlled (restricted) than normal user shells. An extension of the standard Korn Shell that uses hierarchical softkey menus and context-sensitive help. +--------------+--------------------+ | To obtain: | Use the command: | +--------------+--------------------+ | POSIX Shell | /usr/bin/sh ... | | Korn Shell | /usr/bin/ksh ... | | C Shell | /usr/bin/csh ... | | Key Shell | /usr/bin/keysh | +--------------+--------------------+ These shells can also be the default invocation, depending on the entry in the file. See also chsh(1). WARNINGS
Many manual entries contain descriptions of shell behavior or describe program or application behavior similar to ``the shell'' with a ref- erence to ``see sh(1)''. SEE ALSO
For more information on the various individual shells, see: keysh(1) Key Shell description. ksh(1) Korn Shell description. sh-posix(1) POSIX Shell description. csh(1) C Shell description. sh(1)