A user’s shell is the program that runs when they login to a Linux system. The default shell for most users is bash, but there are many other options available. To see a list of available shells on your system, run the following command: cat /etc/shells.
we can have the following shells in the system.
[root@host ~]# cat /etc/shells
/bin/sh
/bin/bash
/sbin/nologin
/bin/dash
/bin/zsh
/bin/tcsh
/bin/csh
There are many different types of shells available on Linux, each with their own strengths and weaknesses. Choosing the right shell can depend on your individual needs and preferences, as well as the type of Linux distribution that you are using.
Check this article to see how to change user shell safely in Linux.