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GROUP(5)                    BSD File Formats Manual                   GROUP(5)

     group -- format of the group permissions file

     The file /etc/group consists of newline separated ASCII records, one per
     group, containing four colon (':') separated fields.  These fields are as

           group     Name of the group.
           passwd    Group's encrypted password.
           gid       The group's decimal ID.
           member    Group members.

     The group field is the group name used for granting file access to users
     who are members of the group.  The gid field is the number associated
     with the group name.  They should both be unique across the system (and
     often across a group of systems) since they control file access.  The
     passwd field is an optional encrypted password.  This field is rarely
     used and an asterisk is normally placed in it rather than leaving it
     blank.  The member field contains the names of users granted the privi-
     leges of group.  The member names are separated by commas without spaces
     or newlines.  A user is automatically in a group if that group was speci-
     fied in their passwd(5) entry and does not need to be added to that group
     in the group file.

     If YP is active, the group file also supports YP exclusions and inclu-

     Lines beginning with a '-' (minus sign) are entries marked as being
     excluded from any following inclusions, which are marked with a `+' (plus

     Lines of the format


     cause the specified group to be included from the group.byname YP map.
     If no group name is specified, or the '+' (plus sign) appears alone on a
     line, all groups are included from the YP map.

     YP references may appear anywhere in the file, but the single '+' form
     should be on the last line, for historical reasons.  Only the first group
     with a specific name encountered, whether in the group file itself, or
     included via YP, will be used.

     Proper YP group support requires consistent group.byname, group.bygid and
     netid.byname YP maps.  See getgrent(3) and getgrouplist(3) for details.

     When YP is enabled but temporarily unavailable, login becomes impossible
     for all users except those having an entry in the netid(5) file.


     passwd(1), setgroups(2), crypt(3), initgroups(3), netid(5), passwd(5),

     The group file format first appeared in Version 6 AT&T UNIX.

     The YP file format first appeared in SunOS.

     The passwd(1) command does not change the group passwords.

     Lines in /etc/group are limited to 1024 characters.  YP groups are not
     affected by this limit.

     Groups are limited to a maximum of 200 members per group.

BSD                              June 20, 2012                             BSD