Adding user to a group
 

- Hey guys how do you assign a user to a certain group using the terminal.

"man useradd" tells you all posibilities.

usermod -a -G GROUP1[,GROUP2,...] username

The subtlety here is that you do not add (assign) users to groups.
You add (assign) groups to users

sudo vi /etc/group

:p

OK--so you are telling me that I can edit this file to add users to groups....touche

BUT!!!
I did a little experiment:
Presuming that the "groups" command gets its info from this file, I disabled my access and ran the groups command. It came back with the GIDs of all my groups, but complained that it could not get the names (because I disabled access to the group file)

So, where did the groups command find the GIDs?
And what would happen if I only edited /etc/group?

All good questions.

Actually I do edit group file directly. Doing a fresh install I find it's the most convenient way. Just open one file and do it all at once, instead of running useradd multiple times. It works that way. Refreshing environment is required to validate changes. Logoff-login will do, too.
Don't know where GID's come from in your test, set in environment? You tell us. ;)

You have nscd running. Stumbled across this one today, looking for something else.

Personally I prefer using gpasswd to add users to groups e.g.

Nope--nothing with ps -e, nothing in synaptic, no man page

:scratch: Don't know then.