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Line 1: {{implementation\|UNIX Shell}} The '''Almquist Shell''', a.k.a. <tt>ash</tt>, is a minimal implementation of aan almost-[[POSIX]] shell, and also a replacement for the [[compatible with::Bourne Shell]]. ~~Almquist Shell~~Ash has more features than the original Bourne Shell, but fewer features than most other shells.; ~~(No~~for example, it lacks arrays!). ~~Almquist~~For ~~Shell~~the most part, it only implements POSIX features, ~~plus~~but it does have a few traditional [[BSD]] ~~traditions~~add-ons, ~~like~~such ~~its~~as <code>local</code> ~~command~~variables in functions. ~~Almquist Shell~~Ash is the default shell, <code>/bin/sh</code>, of some systems. The Almquist Shell does not have any of the internationalization/localization or multi-byte character encoding support required by the POSIX standard, so it is not technically a POSIX-compliant shell. Nonetheless, since it lacks most non-POSIX features, it is helpful in validating that <tt>#!/bin/sh</tt> scripts are not dependent upon such features. In general, if a script works with Almquist Shell, it will probably also work with other popular Bourne-compatible shells, such as the [[Bourne Again SHell]] and [[Z Shell]]. It may not work with the [[Korn Shell]], which uses <tt>typeset</tt> instead of <tt>local</tt>; unfortunately, while bash and zsh treat those commands as synonyms, ash in turn lacks <tt>typeset</tt>. If a script works with Almquist Shell, it will probably also work with [[bash]], [[pdksh]] and [[zsh]]. Further, it will probably work with [[ksh93]] ''unless'' it uses <code>local</code>, which ksh93 lacks. Almquist Shell filled the need for a free shell to replace Bourne Shell. Kenneth Almquist posted [http://groups.google.com/group/comp.sources.unix/msg/2774e7653a8e6274 the first version of Ash] to Usenet group comp.sources.unix at 30 May 1989. It was a clone of SVR3 Bourne Shell. [[BSD]] used Ash for <code>/bin/sh</code>, added features from POSIX, and put a Berkeley copyright on this shell. Line 9: Ash has three major variants: * [[Debian Almquist Shell]] (Dash), which adds support for <tt>echo -n</tt> and <tt>test -a</tt>/<tt>-o</tt> * [http://svnweb.freebsd.org/base/head/bin/sh/ FreeBSD /bin/sh] * [http://cvsweb.netbsd.org/bsdweb.cgi/src/bin/sh/?only_with_tag=MAIN NetBSD /bin/sh] All three variants have similar features. Dash can run on GNU/Linux. Ash is also the shell provided by [[BusyBox]]. == See also ==