This question already has an answer here:

How to add a new user in Ubuntu 12.04, and how i give them a root user privileges

marked as duplicate by Eliah Kagan, Seth, rɑːdʒɑ, con-f-use, belacqua Apr 2 '13 at 17:41

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.


With 12.04 and later

If the user already exists

sudo  usermod -aG sudo <username>

To create the user

adduser <username> --group sudo 

replace username with the name of the user and remove < >

Not the answer you're looking for? Browse other questions tagged or ask your own question.