Installation Of Ubuntu

                                 Ubuntu and root account

By default root account is locked under Ubuntu Linux. Therefore, you cannot login as root or use 'su -' command to become a superuser. To run all administrative command use sudo command. sudo allows a permitted user to execute a command as the superuser or another user. Ubuntu setup your default account (the one created during installation) to run all administrative commands.

For example create a new user called bar, you need to type sudo command as follows:
$ sudo adduser bar
Password:

When sudo asks for a password, you need to supply YOUR OWN password. In other words a root password is not needed. Here are few more examples.

Task: Start / stop / restart services stored in /etc/init.d/ directory

$ sudo /etc/init.d/ssh stop
$ sudo /etc/init.d/networking restart

Task: Avoid typing sudo each and every time

Note that this is not recommended until and unless you are an expert and aware of what you are typing:
$ sudo -i

Above command will start /bin/bash as a root shell so that you can enter a root user command without using sudo command.

How do I login as root user?

Open terminal and simply type the following command:
$ sudo bash
OR
$ sudo -s
Supply your password and you will become a root user.