Shell management

The default shell used by Alpine Linux is the BusyBox variant of the ash shell. This page explains how to use the default shell and various ways to change the default shell in Alpine Linux.

Ash shell

Alpine Linux uses Busybox Ash shell for its default shell. It is a standard POSIX shell derived from Debian Ash variant.

One's ~/.bashrc file (or, alternatively, a different shell alias file) could be considered as a basis, say, for an ~/.ashrc file, reviewing it carefully for syntax/cli variants against that of Ash shell. For non-login, interactive shells refer to Setting alias section.

Tip: Use checkbashisms script to perform basic checks for the presence of bashisms in scripts and help remove them.

Setting alias

For non-login shells, Busybox Ash and other POSIX shells do NOT automatically read a startup file like ~/.ashrc. To ensure that both login and non-login shells work consistently, use ENV environment variable in ~/.profile to refer ~/.ashrc file.

1. Edit the ~/.profile as follows:

   Contents of ~/.profile

   ... export ENV="$HOME/.ashrc"
2. Now aliases can be added in the startup file ~/.ashrc as follows:

   Contents of ~/.ashrc

   # ~/.ashrc: interactive shell configuration for BusyBox Ash # Custom Aliases alias ls='ls --color=auto' alias grep='grep --color=auto' # You may want to put all your additions into a separate file like # ~/.ash_aliases, instead of adding them here directly. if [ -f ~/.ash_aliases ]; then . ~/.ash_aliases fi

Available shells

Most of the popular shells are available in Alpine Linux repositories as can be seen from the below list.

Name	URL	Remarks
bash	https://www.gnu.org/software/bash/bash.html	The GNU Bourne Again shell
zsh	https://www.zsh.org/	Very advanced and programmable command interpreter
fish	https://fishshell.com/	Modern interactive commandline shell
dash	http://gondor.apana.org.au/~herbert/dash/	Small and fast POSIX-compliant shell
oksh	https://github.com/ibara/oksh	Portable OpenBSD ksh, based on pdksh
loksh	https://github.com/dimkr/loksh	A Linux port of OpenBSD's ksh
yash	https://magicant.github.io/yash	Yet another shell
tcsh	https://github.com/tcsh-org/tcsh	extended C-shell
nsh	https://github.com/nuta/nsh	A command-line shell like fish, but POSIX compatible
elvish	https://elv.sh	Friendly and expressive Unix shell
nushell	https://www.nushell.sh	A new type of shell
murex	https://murex.rocks/	Intuitive, typed and content aware shell

To install any of the above shells, say for eg: bash shell:

# apk add bash bash-completion

Change default shell

There are various ways to change the default user shell in Alpine Linux. You can revert back to ash shell at anytime with the same steps.

Note: After performing the below step, you need to log out and login again for these changes to take effect.

By hand

Edit /etc/passwd manually using an editor of your choice. An example line for a user named user is:

Contents of /etc/passwd

... user:x:1000:1000:user:/home/user:/bin/ash ...

Change /bin/ash to point to the path of a shell from /etc/shells. Take care to not delete/mangle the line, as it would make you unable to log in again. The user should be the user you are changing the default login shell for.

Using chsh command

To use chsh command, install the shadow package:

# apk add shadow

And use chsh:

# chsh username

Now enter the path for the shell you want to use (e.g /bin/zsh) and press Enter to confirm this change. The shell should exist in /etc/shells.

/bin/sh

Most applications expect a POSIX-compliant shell to be present in a standard location, /bin/sh. In Alpine Linux, /bin/sh is linked to busybox ash by default, however it is possible to change this by installing a different -binsh package (A list of -binsh packages can be found here). Changing /bin/sh may lead to a difference in script execution speed.

To use dash as /bin/sh:

# apk add dash-binsh

See also

• dash Manual
• Ash README
• Ash source code
• POSIX standard
• stackoverflow on ash shell