gpasswd group gpasswd -a useraccount groupname gpasswd -d useraccount groupname gpasswd -R groupname gpasswd -r groupname gpasswd [-A useraccount,...] [-M useraccount ,...] groupname
gpasswd is used to administer the /etc/group file (and /etc/gshadow file if compiled with SHADOWGRP defined).
System administrator can use:
-A option to define group administrator(s)
-M option to define members and has all rights of group administrators and members.
Group administrator can use:
-a to add users
-d to delete users.
Administrators can use:
-r option to remove group password. When no password is set only group members can use newgrp to join the group.
-R disables access to the group through newgrp command.
gpasswd called by a group administrator with group name only prompts for the group password. If password is set the members can still newgrp without a password, non-members must supply the password.