gpasswd — Administer `/etc/group` and `/etc/gshadow`. More information: <https://manned.org/gpasswd>.

Define group administrators

sudo gpasswd {{[-A|--administrators]}} {{user1,user2}} {{group}}

Set the list of group members

sudo gpasswd {{[-M|--members]}} {{user1,user2}} {{group}}

Create a password for the named group

gpasswd {{group}}

Add a user to the named group

gpasswd {{[-a|--add]}} {{user}} {{group}}

Remove a user from the named group

gpasswd {{[-d|--delete]}} {{user}} {{group}}