Cannot login as super user in Ubuntu?

If you are using Linux Ubuntu OS and you are not able to login as super user by using the su command then try this

$sudo -i 

type the above command and hit enter it will ask you for password enter the password and hit enter.
Now you will be logged in as super user .


Now you may not have to write sudo every time running a command because you are already a super user .
But i prefer that you use sudo it will make your life easier.

To install any new package.
type

sudo apt-get install < package name>

first it will tell you the details of the package like what is the file size and how much space it is going take on your hard disk.

then it will ask you if you want to continue or not.

press y if you want to continue else n and hit enter.

the new package will be installed.