gpasswd

Administer /etc/group and /etc/gshadow. More information: https://manned.org/gpasswd.

• Define group administrators:

sudo gpasswd -A user1,user2 group

• Set the list of group members:

sudo gpasswd -M user1,user2 group

• Create a password for the named group:

gpasswd group

• Add a user to the named group:

gpasswd -a user group

• Remove a user from the named group:

gpasswd -d user group