Korn Shell: Difference between revisions

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Korn Shell, or ksh, is the creation of David Korn at AT&T. This shell combines Bourne Shell syntax with a command-line editor, command history, tilde expansion, arithmetic expressions, arrays, co-processes and several more features. Korn Shell has influenced many later shells; Bourne Again SHell and Z Shell clone several features, and the X/Open and POSIX standards take a few features from Korn Shell. David Korn continues to maintain ksh93, the original implementation.

AT&T freed ksh93 during 2000, using an open-source license. For many years before that, the original Korn Shell was not free; it was only part of AT&T System V and some commercial Unix variants. Therefore, ksh in some systems is not David Korn's shell, but is some other shell, perhaps pdksh or mksh.

Which Korn Shell do I have?

Start ksh and run

$ echo $KSH_VERSION

If the output looks like Version JM 93u 2011-02-08, then you have ksh93.
- Version AJM 93u+ 2012-08-01
If the output looks like @(#)PD KSH v5.2.14 99/07/13.2, then you have pdksh.
If the output looks like @(#)MIRBSD KSH R49 2014/01/11, then you have mksh.
A zsh invoked as ksh sets ZSH_VERSION, not KSH_VERSION.

Links

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-{{stub}}{{implementation|UNIX Shell}}
+{{implementation|UNIX Shell}}
+'''Korn Shell''', or ''ksh'', is the creation of David Korn at AT&T. This shell combines [[Bourne Shell]] syntax with a command-line editor, command history, tilde expansion, arithmetic expressions, arrays, co-processes and several more features. Korn Shell has influenced many later shells; [[Bourne Again SHell]] and [[Z Shell]] clone several features, and the X/Open and [[POSIX]] standards take a few features from Korn Shell. David Korn continues to maintain [[ksh93]], the original implementation.
+AT&T freed ksh93 during 2000, using an open-source license. For many years before that, the original Korn Shell was not free; it was only part of AT&T System V and some commercial Unix variants. Therefore, ''ksh'' in some systems is not David Korn's shell, but is some other shell, perhaps [[Public Domain Korn Shell|''pdksh'']] or [[MirBSD Korn Shell|''mksh'']].
+== Which Korn Shell do I have? ==
+Start ''ksh'' and run
+<syntaxhighlight lang="ksh">$ echo $KSH_VERSION</syntaxhighlight>
+* If the output looks like <code style="background: yellow;">Version JM 93u 2011-02-08</code>, then you have ''[[ksh93]]''.
+** Version AJM 93u+ 2012-08-01
+* If the output looks like <code style="background: yellow;">@(#)PD KSH v5.2.14 99/07/13.2</code>, then you have ''[[pdksh]]''.
+* If the output looks like <code style="background: yellow;">@(#)MIRBSD KSH R49 2014/01/11</code>, then you have ''[[mksh]]''.
+* A ''[[zsh]]'' invoked as ''ksh'' sets ZSH_VERSION, not KSH_VERSION.
+== Links ==
 * [http://www.kornshell.com/ Home Page For The KornShell Command And Programming Language]
 * [[wp:korn shell]]