To assign or add an existing user to an existing group under the Ubuntu terminal is actually quite easy if you know the command and syntax:
sudo usermod -G group -a user
See? Told you so! :P
An Exploring South African
Curiosity, travel, and discovering new places. Craig Lotter's An Exploring South African is primarily a South African travel blog of things to do in and around Cape Town, the Helderberg, and the Cape Winelands.