By default root user is disabled in Ubuntu linux versions. You can simply enable root user in Ubuntu linux by setting a password for root user (Ubuntu). Follow the steps to unlock root user in Ubuntu Linux. Without setting a root password, you may get an error message like ” su: Authentication failure “. This guide will work with all Ubuntu versions like 14.10, 14.04, 13.10. 13.04, 12.04, etc
Unlock root user in Ubuntu Linux
[email protected]:~$ sudo passwd root
[sudo] password for sreekanth: <typing password for the current user>
Enter new UNIX password: <type new password for root user>
Retype new UNIX password: <retype new password for root user>
passwd: password updated successfully
[email protected]:~$ su – root <switching to the root with all root’s own environments>
Password: <type the new password for root user>
[email protected]:~# <you are the root now>