A shell is a command-line interpreter that offers a text-based interface to users. It can be used as command-line interface (CLI) on a terminal emulator or as a script interpreter running in the background.
Typically the shell is the first program started after a user logs in at a terminal. The /etc/passwd file contains information on the default shell for each user on the system.
|bash||app-shells/bash||https://tiswww.case.edu/php/chet/bash/bashtop.html||The Bourne Again Shell, is the default shell on Gentoo. It is used by Portage, Gentoo's default package manager.|
|dash||app-shells/dash||http://gondor.apana.org.au/~herbert/dash/||The Debian Almquist Shell, a small, fast, and posix-compliant shell suited for startup scripts (as /bin/sh replacement).|
|fish||app-shells/fish||https://fishshell.com/||The Friendly Interactive SHell.|
|ksh||app-shells/ksh||http://www.kornshell.com/||The Original Korn Shell, 1993 revision (ksh93).|
|mksh||app-shells/mksh||https://www.mirbsd.org/mksh.htm||An actively developed free implementation of the Korn Shell, and well suited for scripting.|
|tcsh||app-shells/tcsh||http://www.tcsh.org/||an enhanced version of the Berkeley C Shell (csh).|
|xonsh||dev-python/xonsh||http://xon.sh/||A Python-based shell that falls back to bash commands.|
|zsh||app-shells/zsh||http://www.zsh.org/||An advanced shell that is the chosen interactive shell for many users.|
Many shell scripts reference the /bin/sh file; this is generally a symlink to the shell of choice.
For more shell options see the output of the following command (app-portage/eix required):
eix -cC app-shells
Changing the default system shell
System administrators can change the default system shell using the eselect utility.
If it is not installed, emerge the app-eselect/eselect-sh package:
emerge --ask app-eselect/eselect-sh
To list possible shell options use:
eselect sh list
To set dash as the default system shell:
eselect sh set dash
Changing a user's shell
The default shell can be changed using the chsh command. To change the default shell for the current user, type chsh and enter a correct path to the new shell. In the example below, a user named Larry the cow (Larry) is changing his default shell from /bin/bash to /bin/dash:
Changing the login shell for larry Enter the new value, or press ENTER for the default Login Shell [/bin/bash]: /bin/dash
chsh can be used by the super user account to change the default shell for any user.