Linux User Default Groups
My specialty is calling
usermod with wrong params and clear all previous groups. Here are default ones in openSuse (except docker and sudo).
$ groups users disk lp wheel floppy dialout audio video cdrom games input plugdev power netdev scanner docker sudo
there are less groups in the latest setup:
$ groups ivan ivan : users lp wheel audio cdrom dialout disk input video docker
anyways to add all secondary groups again:
$ usermod -aG users,disk,lp,wheel,dialout,audio,video,cdrom,input,docker,sudo ivan
do not use
-g, it modifies primary group. You might need to restart the system to see changes everywhere.