In Ubuntu, by default, there is no root password. Remember, during installation it did not ask you to create a root password.

Therefore you cannot:

• login as root
• use the “su -” command to become the root user.

Though you can:

• use sudo to run a privileged command, with your own password

You can also (though NOT recommended):

• $ sudo -i # run login shell as root
• $ sudo -s # run shell as root
• $ sudo bash # run shell as root
• $ sudo passwd root # set the password for root user

The root user's home directory is /root, not /home/root. This is where you find .profile and .bashrc for the root user, should you choose to open a shell as root.

$ adduser   # create a new user
$    # create a group
$    # add a user to a group
$ passwd <user>   # reset the password for a user
$                 # reset my own password
$                 # add a user to the sudo group
$ sudo -s -u sam  # run shell as a different user