How to install ZSH (optional)
The Z shell (Zsh) is a Unix shell that can be used as an interactive login shell and as a command interpreter for shell scripting. Zsh is an extended Bourne shell with many improvements, including some features of Bash, ksh, and tcsh.
Installing the ZSH is totally optional, if you are happy with bash or any other shell.
Install ZSH on Arch Linux
sudo pacman -S zsh
Install ZSH on Debian
sudo apt install zsh
Set ZSH as a default shell
Note: The chsh command should work on both Debian and Arch Linux.
Check available shells with the following command.
chsh -l
If you see the zsh on the list, set it as default with the following command.
chsh -s /usr/bin/zsh
After you log out and log in, the default shell should be ZSH.
Source(s):