bsd man page for group

GROUP(5)							File Formats Manual							  GROUP(5)

NAME
       group - group file

DESCRIPTION
       Group contains for each group the following information:

       group name
       encrypted password
       numerical group ID
       a comma separated list of all users allowed in the group

       This  is an ASCII file.	The fields are separated by colons; Each group is separated from the next by a new-line.  If the password field is
       null, no password is demanded.

       This file resides in directory /etc.  Because of the encrypted passwords, it can and does have general read permission and can be used, for
       example, to map numerical group ID's to names.

FILES
       /etc/group

SEE ALSO
       setgroups(2), initgroups(3X), crypt(3), passwd(1), passwd(5)

BUGS
       The passwd(1) command won't change the passwords.

7th Edition							   May 15, 1985 							  GROUP(5)