gpasswd(1) -- Linux man page
NAMEgpasswd - administer the /etc/group file
gpasswd -a user group
gpasswd -d user group
gpasswd -R group
gpasswd -r group
gpasswd [-A user,...] [-M user,...] group
DESCRIPTIONgpasswd is used to administer the /etc/group file (and /etc/gshadow file if compiled with SHADOWGRP defined). Every group can have administrators, members and a password. System administrator can use -A option to define group administrator(s) and -M option to define members and has all rights of group administrators and members.
Group administrator can add and delete users using -a and -d options respectively. Administrators can use -r option to remove group password. When no password is set only group members can use newgrp(1) to join the group. Option -R disables access to the group through newgrp(1) 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(1) without a password, non-members must supply the password.
FILES/etc/group - group information
/etc/gshadow - shadow group information
SEE ALSOnewgrp(1), groupadd(8), groupdel(8), groupmod(8), grpck(8)
AUTHORRafal Maszkowski <email@example.com>