For example: sudo /etc/init. d/networking stop stops the network service, and sudo adduser adds a new user to the system. Both of these tasks require root access. You will be prompted to enter your password before sudo runs the command. Linux stores your password for 15 minutes so you won’t have to keep typing it.
For example: type gksudo gedit /etc/fstab to open the “fstab” file in GEdit, an editing program with a GUI. If you’re using the KDE Window Manager, use kdesudo instead of gksudo.
Enter the command sudo passwd root. This will create a password for root, essentially “enabling” the account. Don’t forget this password. Type sudo -i. Enter the root password when prompted. The prompt will change from $ to #, indicating you have root access.
Enabling the root user can put your system at risk and is not recommended by Ubuntu. [5] X Research source
To disable the root account, type sudo passwd -dl root. [7] X Research source