Permissions

d

groups command  you can also use  id -Gn

chmod

ugoa  User category  user, group,other ,all

rwx Read Write Execute

UGO

Commonly Used Permissions

chgrp  changes the group

umask [-S] [mode]

Common unmask modes

022

002

077

007

Umask permutation

umask 0022 is the same as umask 022

chmod 06400 is the same as chmod 644