php man page for group

GROUP(5)						     Linux Programmer's Manual							  GROUP(5)

NAME
       group - user group file

DESCRIPTION
       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:

	   group_name:password:GID:user_list

       The fields are as follows:

       group_name  the name of the group.

       password    the (encrypted) group password.  If this field is empty, no password is needed.

       GID	   the numeric group ID.

       user_list   a list of the usernames that are members of this group, separated by commas.

FILES
       /etc/group

BUGS
       As the 4.2BSD initgroups(3) man page says: no one seems to keep /etc/group up-to-date.

SEE ALSO
       chgrp(1), gpasswd(1), groups(1), login(1), newgrp(1), sg(1), getgrent(3), getgrnam(3), gshadow(5), passwd(5)

COLOPHON
       This  page is part of release 4.15 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 https://www.kernel.org/doc/man-pages/.

Linux								    2016-10-08								  GROUP(5)