I am trying to change a users group - and for some reason it does not seem to work.

Here you can see this user has a group same as his username.

I am trying to change this but is not working. What am I doing wrong?

I am trying to specify user ttrimble have a primary (-g) group of fcat and also be part of (-G) users group.

It does not seem to work.

Have a look in /etc/group to see which users are members of which groups.

Haven't you simply posted the output of ls -l? All this is showing is that the directory ttrimble is owned by user ttrimble and group ttrimble and reflects your grouping at the time ttrimble created the directory (changing the user's groups won't change file ownerships). I assume that the group ttrimble still exists, even if the user ttrimble doesn't belong to it.

If you want to change the group, simply use

chown :fcat /home/ttrimble

or whatever the relevant path is. You can use the -R option to change all subdirectories and files within /home/ttrimble if you want

I guess I don't understand groups that well. I have a user "ttrimble" on a server and I want to make his primary group "fcat" but I also want him to have access to some folders that can only be accessed by the "cvs" group. I would assume I could also make him a member of "cvs" while he maintains "fcat" as his primary or default group, no?

How can I verify what group(s) "ttrimble" is currently a member off and then secondly - how would I usermod the above scenario in a correct CLI syntax?

I looked in /etc/group but there are so many users - is there no other way simply list a specific user and have Linux output all of the specified users known groups?

You can change a users primary group but that won't change existing ownerships on files already in place.

You'll need to use the chown command to change any existing groups you want his new group to own.

And like said before, you may just want to add him to the group that has access to cvs, etc.

You can see current groups by doing an "id" on his username:

id ttrimble

I found out that if I run the command:

You can see I am a member of the wheel group and also a member of "ctia" which answers my question above .

It looks like it is now working with the usermod command - I was just looking in the wrong place.

Thanks!