Shell

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.

Available software

Name	Package	Homepage	Description
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.

Note
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):

user $eix -cC app-shells

Configuration

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:

root #emerge --ask app-eselect/eselect-sh

To list possible shell options use:

root #eselect sh list

To set dash as the default system shell:

root #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:

user $chsh

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.