group(4)
NAME
group - group file
DESCRIPTION
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
where
groupname
The name of the group.
gid The group's unique numerical ID (GID) within the sys-
tem.
user-list
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
ignored.
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
time.
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.
EXAMPLES
Example 1: Sample of a group file.
Here is a sample group file:
root::0:root
stooges:q.mJzTnu8icF.:10:larry,moe,curly
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
stooges.
If the group file was:
root::0:root
stooges:q.mJzTnu8icF.:10:larry,moe,curly
+:
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.
SEE ALSO
groups(1), grpck(1B), newgrp(1), getgrnam(3C),
initgroups(3C), nsswitch.conf(4), unistd(3HEAD)
System Administration Guide: Basic Administration
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