Use "sudo usermod -a -G example_group example_user" to add a user to a group. To add a user to multiple groups at once, separate groups by commas, like "sudo usermod -a -G group1,group2,group3 example ...

OK, actually, they're fit to be tied. That's because millions of users have been using CentOS as a stable point distribution for their servers, virtual machines, and appliances. These aren't just ...