Ubuntu is based on the sudo command, apparently eliminating the possibility of directly using the root account.

Sometimes, when a series of commands must be executed as root from console, it becomes “annoying” to use sudo command.

Even though it doesn’t seem possible you can authenticate as root.

First of all the user must have root right,  when using sudo command!

The authentication can be done in two ways:
– sudo session:

1sudo -s

– using su:

1sudo su

Of course the root authorization is only for the current console. But from this console, for example other consoles can be opened, and they will be running as root.