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 exclusive for running
legacy shell scripts. It is built on
mksh; refer to its
manual page for details on the scripting language.
LEGACY MODE¶
lksh has the following differences from
mksh:
- lksh is not suitable for use as
/bin/sh.
- There is no explicit support for interactive use, nor
any command line editing code. Hence, lksh is not
suitable as a user's login shell, either; use mksh
instead.
- The
KSH_VERSION string
identifies lksh as “LEGACY KSH” instead of
“MIRBSD KSH”.
- Some mksh specific extensions are
missing; specifically, the -T command-line option.
- 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.
- lksh, unlike AT&T
UNIX ksh, does not keep file descriptors > 2
private.
- lksh parses leading-zero numbers as
octal (base 8).
- Integers use the host C environment's
long type, not int32_t.
Unsigned arithmetic is done using unsigned long, not
uint32_t. Neither value limits nor wraparound is
guaranteed. Dividing the largest negative number by -1 is Undefined
Behaviour (but might work on 32-bit and 64-bit long
types).
- lksh only offers the traditional ten
file descriptors to scripts.
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 specified. Parsing numbers with leading zero digits or
“0x” is relatively recent in all
pdksh
derivates, but supported here for completeness. It might make sense to make
this a run-time option, but that might also be overkill.
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.
