How to Shutdown from Terminal in Red Hat Linux 6.0

Suppose you are logged in as a normal user say:

user1@localhost ~]$

Now you need to switch to root user using switch user command
The command is

su -

Shell prompt you to enter rot user password like this

user1@localhost ~]$ su -
password:

Type your password and press enter.

Now you are switched to root user.

root@localhost ~]$ 

Type this command

 root@localhost ~]$  init 0

Thats all done.