1) Add User
2) Delete user
3) Modify user
4) Add Group
5) Delete group
6) Modify group
7) Add User to Group
Use useradd command to add new users to existing group (or create a new group and then add user). If group does not exist, create it. Syntax:
Syntax:
useradd -G {group-name1},{group-name2} username (for secondary group)
useradd -g {group-name} username (for primary group)