BusyBox
Alpine Linux is built around musl libc and busybox. To minimize footprint, Alpine Linux comes with BusyBox by default. BusyBox provides replacements for most of the utilities usually found in GNU coreutils, util-linux, etc. Built-in utility programs called as applets share code for many common operations. Invoking BusyBox with no argument lists the applets that have been compiled into BusyBox binary. Refer BusyBox Manual for options supported by BusyBox.
BusyBox is set up as an endpoint for numerous symlinks that substitute various utilities. The utilities in BusyBox generally have fewer options and hence missing some functionality. Refer How to get regular stuff working page for installing the relevant packages to replace BusyBox symlinks.
Ash shell
Alpine Linux uses Busybox Ash for its default shell. To change the default shell to other shells like bash, zsh, fish etc..refer change default shell.
Aliases
When using Ash shell, one can’t set aliases in the ~/.profile, but environment variables can be set in it. In order to use aliases with Busybox Ash, you must set the ENV environment variable to refer the aliases file.
First create the file /etc/profile.d/profile.sh as follows:
Contents of /etc/profile.d/profile.sh
Next create the file ~/.config/ash/profile as follows:
Contents of ~/.config/ash/profile
Now aliases can be added in the file ~/.config/ash/ashrc:
Contents of ~/.config/ash/ashrc
vi
Busybox uses tiny vi, a small 'vi' clone. Refer Busybox vi tutorial for an excellent introduction.
Replacing BusyBox Utilities
The utilities in BusyBox generally have fewer options than their full-featured GNU counterparts. If you find certain utilities in busybox lacking in features or options, it is easy to replace respective endpoints by their equivalent full-featured utilities.