group - group file


     The group file is a local source of group  information.  The
     group  file  can  be  used  in  conjunction with other group
     sources,  including   the   NIS   maps    group.byname   and
     group.bygid  and  the  NIS+  table   group. Programs use the
     getgrnam(3C) routines to access this information.

     The  group file contains a one-line  entry  for  each  group
     recognized by the system, of the form:

          groupname:password: gid:user-list


           The name of the group.

     gid   The group's unique numerical ID (GID) within the  sys-

           A comma-separated list of users allowed in the group.

     The maximum value of the  gid field is 2147483647. To maxim-
     ize  interoperability  and compatibility, administrators are
     recommended to assign groups using the range of  GIDs  below
     60000 where possible.

     If the password field is empty,  no  password  is  demanded.
     During  user  identification and authentication, the supple-
     mentary group access list is initialized  sequentially  from
     information  in  this file. If a user is in more groups than
     the system is configured for, {NGROUPS_MAX}, a warning  will
     be   given  and  subsequent  group  specifications  will  be

     Malformed entries cause routines  that  read  this  file  to
     halt,  in  which  case  group  assignments specified further
     along are never made.  To prevent this from  happening,  use
     grpck(1B)  to  check  the  /etc/group  database from time to

     Previous releases used a group entry beginning  with  a  `+'
     (plus  sign)  or `-' (minus sign) to selectively incorporate
     entries from NIS maps for group. If still required, this  is
     supported  by  specifying  group:compat in nsswitch.conf(4).
     The  ``compat''  source  may  not  be  supported  in  future
     releases.  The  preferred sources are, ``files'' followed by
     ``nisplus''. This has the effect of incorporating the entire
     contents of the NIS+ group table after the  group file.


     Example 1: Sample of a group file.

     Here is a sample  group file:


     and the sample group entry from nsswitch.conf:

     group: files nisplus

     With these entries, the  group  stooges  will  have  members
     larry,  moe,  and   curly, and all groups listed in the NIS+
     group table are effectively incorporated after the entry for

     If the  group file was:


     and the group entry from nsswitch.conf:

     group: compat

     all  the  groups  listed  in   the   NIS   group.bygid   and
     group.byname  maps  would  be effectively incorporated after
     the entry for stooges.


     groups(1),     grpck(1B),      newgrp(1),      getgrnam(3C),
     initgroups(3C), nsswitch.conf(4), unistd(3HEAD)

     System Administration Guide: Basic Administration

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