1. vim /etc/group 2. Could not find "admin" group 3. adm:x:4:MYUSERNAME << added it here, because I assume this is "admin" 4. quit the vim editor...and tried it under my username...and it DOESNT WORK!
The "adm" group is not the same as the "admin" group.
Also, you should never edit /etc/group by hand. If you mess something up, you can end up with a broken system.
The easiest command for adding someone to a group is like this:
gpasswd -a MYUSERNAME admin
If you're trying to give someone sudo-rights, can also just run
visudo as root, and add a line like this to the file:
MYUSERNAME ALL=(ALL) ALL
If you want to give sudo-rights to everyone in the "adm" group, you can do something like this
%adm ALL=(ALL) ALL