Being new to Linux administration, I'm a little confused about the following commands:
useradd usermod groupadd groupmod
I've just finished reading the user administration book in the Linux/Unix Administrator's handbook, but some things are still a little hazy.
useradd seems straight forward enough:
useradd -c "David Hilbert" -d /home/math/hilbert -g faculty -G famous -m -s /bin/sh hilbert
I can add "David Hilbert" with username
hilbert , setting his default directory, shell, and groups. And I think that
-g is his primary/default group and
-G are his other groups.
So these are my next questions:
- Would this command still work if the groups
famousdid not exist? Would it just create them?
- If not, what command do I use to create new groups?
- If I remove the user
hilbertand there are no other users in those groups, will they still exist? Should I remove them?
- After I run the
useraddcommand above, how do I remove David from the
famousgroup, and reassign his primary group to
hilbertwhich does not yet exist?