[CentOS] the correct way to add users to another group???

Sat Feb 18 22:41:10 UTC 2006
Zeb Fletcher <zeb.fletcher at gmail.com>

rado wrote:
> kk, I am guilty of easily just booting up in Kde's gui, start/system
> settings/users and groups but then also I'd rather do it from the bash
> console.
> after googling around a good bit I am still not exactly sure of the
> proper way to do this.
> I want to add a user to another group w/out removing the groups the user
> already belongs to.
> in man usermod:
>       -G group,[...]
>               A  list of supplementary groups which the user is also
> a member of.  Each group is separated from the next by a comma, with  no
>               intervening  whitespace.   The  groups  are subject to the
> same restrictions as the group given with the  -g  option.   If  the
>               user  is currently a member of a group which is not
> listed, the user will be removed from the  group.  This  behaviour  can
> be changed  via  -a option, which appends user to the current
> supplementary group list.
> ok...I kinda get this but unclear of the exact format and I am super
> fearful of ripping up my userbase.
> Here is what I think it should be:
> # usermod <user> -a -G <group> 
> where the user's name is say..."pete" and I want him to be added to the
> group "tech":
> # usermod pete -a -G tech
> Say pete is already in groups ummm, sales,admin, and help. After
> administering the above command, would pete still be in sales,
> admin,help, and now tech? I am interested in the simplest, correct way
> to do this.
> thx,
> John Rose
> _______________________________________________
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> CentOS at centos.org
> http://lists.centos.org/mailman/listinfo/centos

The command should be
# usermod -G <group1,group2...> <username>
When doing it this way you need to specify ALL the groups the user 
belongs to as this does not append to the current list. So to get a list 
of groups a user may be associated with type
# groups <username>
Then take the output to be used with usermod command. Or you can just 
edit the /etc/groups file by hand