You want to use sudo -i or su - to log into root. sudo su anything is superfluous, because you probably should be using sudo -i or sudo -s, which are roughly equivalent, depending if you want to simulate a login (su - or sudo -i) or not (su or sudo -s).1 When to use su -? You want to log into root using the root password. Typically you must be in the wheel group (check your PAM configuration).| Winny's Blog