GNU Bash

Bash is the GNU Project's shell—the Bourne Again SHell. This is an sh-compatible shell that incorporates useful features from the Korn shell (ksh) and the C shell (csh). It is intended to conform to the IEEE POSIX P1003.2/ISO 9945.2 Shell and Tools standard. It offers functional improvements over sh for both programming and interactive use. In addition, most sh scripts can be run by Bash without modification.

The improvements offered by Bash include:

  • command-line editing,
  • unlimited size command history,
  • job control,
  • shell functions and aliases,
  • indexed arrays of unlimited size,
  • integer arithmetic in any base from two to sixty-four.

The maintainer also has a Bash page which includes Frequently Asked Questions.


Stable releases can be found on the main GNU server (HTTPSHTTPFTP) and its mirrors; please use a mirror if possible.


Documentation for Bash is available online, as is documentation for most GNU software. You may also find information about Bash by running info bash or man bash, or by looking at /usr/share/doc/bash/, /usr/local/share/doc/bash/, or similar directories on your system. A brief summary is available by running bash --help.

Mailing lists

Announcements about Bash and most other GNU software are made on

To subscribe to these or any GNU mailing lists, please send an empty mail with a Subject: header of just “subscribe” to the relevant -request list. For example, to subscribe yourself to the GNU announcement list, you would send mail to <>. Or you can use the web interface.

Getting involved

Development of Bash, and GNU in general, is a volunteer effort, and you can contribute. For information, please read How to help GNU. If you'd like to get involved, it's a good idea to join the discussion mailing list (see above).

For development sources, bug and patch trackers, and other information, please see the Bash project page at
Translating Bash
To translate the program messages into other languages, please refer to the Translation Project page for Bash. New translations or updates to the existing strings will not be incorporated into Bash if they are sent elsewhere. For more information, see the Translation Project home page.
Bash is currently maintained by Chet Ramey. Please use the mailing lists for contact.


Bash is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version.