This is how to change your login shell with the chsh command. This requires the user to log out and then back in to use their new shell.
ubuntu ~ $ sudo chsh -s /bin/bash
Only a shell listed in /etc/shells may be used. But this is a very quick way to change the user account shell on Linux.
These are the valid shells on my system.
ubuntu ~ $ cat /etc/shells # /etc/shells: valid login shells /bin/sh /bin/dash /bin/bash /bin/rbash /usr/bin/tmux /usr/bin/screen /bin/tcsh /usr/bin/tcsh
If you install a new shell from source, be sure to add the path to this file, or it will not work properly.