group - user group file
/etc/group is a text file which defines the groups on the system.
There is one entry per line, with the following format:
The field descriptions are:
the name of the group.
the (encrypted) group password. If this field is empty, no
password is needed.
GID the numerical group ID.
a list of the usernames that are members of this group,
separated by commas.
As the 4.2BSD initgroups(3) man page says: No-one seems to keep
login(1), newgrp(1), getgrent(3), getgrnam(3), passwd(5)
This page is part of release 3.24 of the Linux man-pages project. A
description of the project, and information about reporting bugs, can
be found at http://www.kernel.org/doc/man-pages/.