Korn Shell from Wikipedia, the Free Encyclopedia

Korn shell From Wikipedia, the free encyclopedia

KornShell (ksh) is a Unix shell which was developed by David Korn at Bell Labs in the early 1980s and announced at KornShell USENIX on July 14, 1983.[1][2] The initial development was based on Bourne shell source code.[6] Other early contributors were Bell Labs developers Mike Veach and Pat Sullivan, who wrote the Emacs- and vi-style line editing Original author(s) David Korn [7] modes' code, respectively. KornShell is backward-compatible with the Bourne shell and includes many features of Initial release 1983[1][2] the C shell, inspired by the requests of Bell Labs users. Stable release ksh93v / June 1, 2013[3] Development status Active Contents Written in C Operating system Unix 1 Design 2 History Available in English 3 Variants Type Unix shell 4 See also License AT&T KornShell: 5 References Eclipse Public 6 Further reading 7 External links License[4] pdksh: Mostly public domain with Design some GPL mksh: MirOS [5] KornShell complies with POSIX.2, Shell and Utilities, Command Interpreter (IEEE Std 1003.2-1992.) Major differences Licence between KornShell and the traditional Bourne shell include: dtksh: Proprietary Website www.kornshell.org Job control, command aliasing, and command history designed after the corresponding C shell features. Job (http://www.kornshell.org/) control was added to the Bourne Shell in 1989.[8] A choice of three command line editing styles based on vi, Emacs, and XEmacs. Associative arrays and built-in floating point arithmetic operations (only available in the ksh93 version of KornShell). Dynamic extensibility of built-in commands (as of ksh93).

History

Until 2000, KornShell remained AT&T′s proprietary software. Since then it has been open source software, originally under a license particular to AT&T but, since the 93q release in early 2005, it has been licensed under the Eclipse Public License.[4] KornShell is available as part of the AT&T Software Technology (AST) Open Source Software Collection. As KornShell was initially only available through a proprietary license from AT&T, a number of free and open source alternatives were created. These include pdksh, mksh, GNU bash, and zsh.

The functionality of the original KornShell, ksh88, was used as a basis for the standard POSIX.2, Shell and Utilities, Command Interpreter (IEEE Std 1003.2-1992.) Interaction with pdksh in OpenBSD (default shell) Some vendors still ship their own version of the older ksh88, sometimes with extensions. ksh93 is still maintained by its author. Releases of ksh93 are versioned by appending a letter to the name; the current version is ksh93u, following ksh93t+ (which followed ksh93t); ksh93v is in the beta phase.[9]

As "Desktop KornShell", dtksh, the ksh93 was distributed as part of the CDE.[10] This version also provide shell-level mappings for Motif widgets. It was intended as competitor to tcl/tk.[11]

The original KornShell, ksh88, is the default shell on AIX since version 4,[12][13] with ksh93 available separately.[14]

UnixWare 7 includes both ksh88 and ksh93. The default Korn shell is ksh93 supplied as /usr/bin/ksh, and the older version is available as /usr/bin/ksh88.[15] UnixWare also includes dtksh when CDE is installed.

Variants

There are several software products related to KornShell:

dtksh — a fork of ksh93, which is part of CDE. tksh — a fork of ksh93, which provides access to the Tk widget toolkit. oksh — a fork of OpenBSD′s flavour of KornShell, which supports GNU/Linux only; it is used as the default shell in DeLi Linux. mksh — a free implementation of the KornShell language, forked from pdksh, from MirOS BSD licensed under permissive (though not public domain) terms; specifically, the MirOS Licence.[5] Outside of BSD, this variant has replaced pdksh on Debian.[16] SKsh — an AmigaOS flavour, which provides several Amiga-specific features, such as ARexx interoperability. MKS Inc.′s MKS Korn shell — a proprietary implementation of the KornShell language from Microsoft Windows Services for UNIX (SFU) up to version 2.0; according to David Korn, the MKS Korn shell was not fully compatible with KornShell in 1998.[17][18] in SFU version 3.0 Microsoft replaced the MKS Korn shell with a new POSIX.2-compliant shell as part of Interix.[19] KornShell is included in UWIN, a Unix compatibility package by David Korn.[20]

See also

Comparison of computer shells List of Unix utilities The test program The find program

References

1. Ron Gomes (Jun 9, 1983). "Toronto USENIX Conference Schedule (tentative)". Newsgroup: net.usenix. Retrieved Dec 29, 2010. 2. Guy Harris (Oct 10, 1983). "csh question". Newsgroup: net.flame. Retrieved Dec 29, 2010. 3. http://www2.research.att.com/~astopen/download/notes.html 4. http://www2.research.att.com/~astopen/download/gen/ast-open.html 5. https://www.mirbsd.org/mksh.htm 6. Korn, David G. (October 26, 1994), "ksh - An Extensible High Level Language", Proceedings of the USENIX 1994 Very High Level Languages Symposium (USENIX Association), retrieved February 5, 2015, "Instead of inventing a new script language, we built a form entry system by modifying the Bourne shell, adding built-in commands as necessary." 7. Bolsky, Morris I.; Korn, David G. (1989). "Acknowledgements". The KornShell Command and Programming Language. Englewood Cliffs, NJ: Prentice Hall. pp. xii. ISBN 0-13-516972-0. 8. http://www.in-ulm.de/~mascheck/bourne/#variants Bourne Shell evolvement 9. http://lists.research.att.com/pipermail/ast-users/2014q2/004548.html 10. Bill Rosenblatt; Arnold Robbins (2002). Learning the Korn Shell (2 ed.). O'Reilly Media, Inc. pp. viii–ix. ISBN 978-0-596-00195-7. 11. J. Stephen Pendergrast (1995). Desktop KornShell graphical programming. Addison-Wesley. p. 359. ISBN 978-0-201-63375-7. 12. Casey Cannon; Scott Trent; Carolyn Jones (1999). Simply AIX 4.3. Prentice Hall PTR. p. 21. ISBN 978-0-13-021344-0. 13. http://publib.boulder.ibm.com/infocenter/aix/v6r1/index.jsp?topic=/com.ibm.aix.cmds/doc/aixcmds5/sh.htm 14. http://publib.boulder.ibm.com/infocenter/aix/v6r1/index.jsp?topic=/com.ibm.aix.baseadmn/doc/baseadmndita/korn_shell_enhanced.htm 15. http://uw714doc.sco.com/en/DIFFS/UNIX95_Conformance.html#ksh-93_vs_ksh-88 16. https://people.debian.org/~spaillard/Debian_Release_Notes/mksh.html 17. "David Korn Tells All". Slashdot. Retrieved 2009-10-22. 18. "Jerry Feldman — USENIX NT/LISA NT conference attendee". Lists.blu.org. Retrieved 2009-10-22. 19. "Windows Services for UNIX Version 3.0". Technet.microsoft.com. Retrieved 2009-10-22. 20. Anatole Olczak (2001). The Korn shell: Unix and Linux programming manual. Addison-Wesley Professional. p. 4. ISBN 978-0-201-67523-8.