Alpine Linux comes with BusyBox. It is described as “The Swiss Army Knife of Embedded Linux.” BusyBox combines tiny versions of many standard UNIX utilities into a single small executable, including /bin/sh. By default, bash is not included with BusyBox and Alpine Linux. The postmarketOS project, which is designed to run on mobile devices, is based on Alpine Linux. Many Docker images are also based upon Alpine, and you may install bash shell in Docker-based images too. This page shows how to install a bash shell in Alpine Linux using the apk command.
How do I install bash shell in Alpine Linux?
It is easy to have bash installed but this does not mean the symlinks to busybox are gone. The syntax is as follows with apk command:
# apk update
# apk upgrade
# apk add bash
Here is how it looks:
(1/4) Installing ncurses-terminfo-base (6.1_p20200118-r4) (2/4) Installing ncurses-libs (6.1_p20200118-r4) (3/4) Installing readline (8.0.1-r0) (4/4) Installing bash (5.0.17-r1) Executing bash-5.0.17-r1.post-install Executing busybox-1.31.1-r19.trigger OK: 11 MiB in 23 packages
Get a list of valid login shells on Alpine Linux using the cat command:
# cat /etc/shells
Outputs:
# valid login shells /bin/sh /bin/ash /bin/bash
How to install bash man pages and other docs
To install bash documentation, enter:
# apk add bash-doc
To install bash automatic command line completion install, run:
# apk add bash-completion
Sample session:
Fig.01: How to get bash working on Alpine Linux
How to set bash as login shell
To use bash as a shell just type bash:
$ bash
To login to alpine Linux LXD vm from host, enter:
$ lxc exec alpine-lxd-vm-name-here bash
One can change root shell to bash shell using the following method:
# vi /etc/passwd
Find user name and the default shell such as /bin/ash:
root:x:0:0:root:/root:/bin/ash
Replace it with /bin/bash:
root:x:0:0:root:/root:/bin/bash
Customize bash shell
Here is a sample file displayed using the cat command
cat ~/.bashrc
## OR ##
cat ~/.bash_profile
Sample config:
alias update='apk update && apk upgrade' export HISTTIMEFORMAT="%d/%m/%y %T " export PS1='\u@\h:\W \$ ' alias l='ls -CF' alias la='ls -A' alias ll='ls -alF' alias ls='ls --color=auto' source /etc/profile.d/bash_completion.sh export PS1="\[\e[31m\][\[\e[m\]\[\e[38;5;172m\]\u\[\e[m\]@\[\e[38;5;153m\]\h\[\e[m\] \[\e[38;5;214m\]\W\[\e[m\]\[\e[31m\]]\[\e[m\]\\$ "
See Customize the bash shell environments wiki page for more info.
How to find bash shell version
One can type the following command:
bash --version
The current bash version:
GNU bash, version 5.0.17(1)-release (x86_64-alpine-linux-musl) Copyright (C) 2019 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later This is free software; you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.
See how to find out what shell I am using on Linux/Unix” for more info.
Adding bash to Alpine Docker image
Add the following command to your Docker config file to install bash shell:
RUN apk add --no-cache bash
Conclusion
You learned how to install bash shell on Alpine Linux along with documents, man pages and configure the bash shell as per your needs. I suggest you read bash man pages/docs here online for more info.
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It was helpful to replace sh with bash.