How to Join an Ubuntu Server 12.04 to a domain in 6 steps

1^st)

^{sudo bash}

2^nd)

^{enter password of sudo user}

3^rd)

apt-get install likewise-open

4^th)

^{be patient and wait up} to 5 minutes depending on your machines speed

5^th)

domainjoin-cli join “yourdomain.local” “A_User_with_Admin_right”

6^th

Enter your password and wait up to 5 minutes

   ********

Next you need to add yourself to the sudo user group
  ******** 



credits go to:
https://help.ubuntu.com/10.04/serverguide/likewise-open.html