Quickly Add Users to Groups in Ubuntu 12.04 (Precise Pangolin)
You probably already know how difficult it is to manage groups in Ubuntu with Unity as your default session. In previous versions of Ubuntu with classic gnome desktop, one could easily add/remove users from groups by using the user management tool. Not anymore. That tool is gone and the only way to manage groups in Ubuntu now is by the command-line. This brief tutorial is going to show you how to quickly add users to existing groups in Ubuntu 12.04.
Objectives:
- Add users to existing groups in Ubuntu 12.04
- Enjoy!
To get started, press Ctrl – Alt – T on your keyboard to open Terminal. When it opens, run the commands below to add a user to a group.
sudo adduser <username> <group_name>
For example, to add an existing user to the sudo group so the user can run the sudo commands, run the commands below.
sudo adduser <username> sudo
That’s it! Do this everytime you wish to modify a group by adding existing users.
Enjoy!

Thanks a lot!