Supposing you want to make bash your default shell, you'll use:

chsh -s /bin/bash

The chsh command allows you to change the user login shell. -s lets you specify the shell. Without -s chsh will enter interactive mode.

Customize your favorite contact's ringtones!
1 minute

Sometimes, when you are busy or out and about and your iPhone starts ringing, you don't want to pick it up, but you know it might be so-and-so with that important call you've been waiting on.