You're right that su and sudo are different in *nix. But sudo is more applicable here, because sudo is asking for root privileges, whereas su is simply asking to Switch User. In order to use su, you only need to know the password of the account to which you are switching; if you don't specify an account, then you are asking to become root. In Android, however, there is no root password, nor any other accounts, so su is the command known by users to run in a terminal to gain root privileges. – Stephen Schrauger Jun 11 '13 at 13:33