How can I change shell in Ubuntu? [duplicate]

To change a shell, use the bare chsh command. This will prompt you for the new shell. You do not have to run anything as root.

When running as root, you can use chsh to change other users shells. The syntax you want to use it this. You can change your own shell without root rights.

chsh -s /bin/bash username

You can change your default shell for your user by using the usermod command.

sudo usermod -s <shell> <username>

replace with the name of the shell you want to use (i.e. /bin/bash) and with the username for which you want to change it.

This will set the default shell for the username selected in the /etc/passwd file.