In Linux (and Unix in general), there is a SuperUser named Root. The Windows equivalent of Root is Administrators group. The SuperUser can do anything and everything, and thus doing daily work as the SuperUser can be dangerous.
By default, the root account in Ubuntu Live mode hasn’t password. That’s mean you can’t do anythings with sudo command. Sometimes, you need the Live mode to recover, fix GRUB… and it’s required root privileges needed for the task at hand.
To manually set a password for the root user, type in the following in the shell:
After that you are asked to type in the new root password twice. Finally, your root user has its own password.