List all groups on this system:

cut -d: -f1 /etc/group

List user's groups:

groups

Add a user to group:

gpasswd -a <userName> <groupName>

Remove user from group:

gpasswd -d <userName> <groupName>

Reload group without logout:

newgrp <new group name>

View disk usage:

ncdu -x -q   # ncdu packages is required

• Users and groups - ArchWiki