User group file
The /etc/group file is a text file that defines the groups on the system. There is one entry per line, with the following format:
The fields are as follows:
the name of the group.
the (encrypted) group password. If this field is empty, no password is needed.
the numeric 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 /etc/group up-to-date.
This page is part of release 3.74 of the Linux man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at http://www.kernel.org/doc/man-pages/.