Creation User
useradd [option] ussername
Deletion User
userdel [option] username
Serching User Information
id userName
Switching User
su feige
Modification User Information
usermod [option] Username
Change Users Password
passwd [option] Username
Addition Group
groupadd [option] groupname
Deletion Group
groupdel groupname
Change User Group
groupmod [option] usergroup
Switching group
newgrp groupname