1.\" Copyright (c) 1980, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. Neither the name of the University nor the names of its contributors 13.\" may be used to endorse or promote products derived from this software 14.\" without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.\" From: @(#)group.5 8.3 (Berkeley) 4/19/94 29.\" $FreeBSD: src/share/man/man5/group.5,v 1.29 2006/02/18 16:48:56 brueffer Exp $ 30.\" $DragonFly: src/share/man/man5/group.5,v 1.6 2007/04/07 19:29:52 swildner Exp $ 31.\" 32.Dd September 29, 1994 33.Dt GROUP 5 34.Os 35.Sh NAME 36.Nm group 37.Nd format of the group permissions file 38.Sh DESCRIPTION 39The 40.Nm 41file is the local source of group information. 42It can be used in conjunction with the Hesiod domain 43`group', and the NIS maps `group.byname' and `group.bygid', 44as controlled by 45.Xr nsswitch.conf 5 . 46.Pp 47The file 48.Nm 49consists of newline separated 50.Tn ASCII 51records, one per group, containing four colon 52.Ql \&: 53separated fields. 54These fields are as follows: 55.Bl -tag -width password -offset indent -compact 56.It group 57Name of the group. 58.It passwd 59Group's 60.Em encrypted 61password. 62.It gid 63The group's decimal ID. 64.It member 65Group members. 66.El 67.Pp 68Lines whose first non-whitespace character is a pound-sign (#) 69are comments, and are ignored. 70Blank lines that consist 71only of spaces, tabs or newlines are also ignored. 72.Pp 73The 74.Ar group 75field is the group name used for granting file access to users 76who are members of the group. 77The 78.Ar gid 79field is the number associated with the group name. 80They should both be unique across the system (and often 81across a group of systems) since they control file access. 82The 83.Ar passwd 84field 85is an optional 86.Em encrypted 87password. 88This field is rarely used 89and an asterisk is normally placed in it rather than leaving it blank. 90The 91.Ar member 92field contains the names of users granted the privileges of 93.Ar group . 94The member names are separated by commas without spaces or newlines. 95A user is automatically in a group if that group was specified 96in their 97.Pa /etc/passwd 98entry and does not need to be added to that group in the 99.Nm 100file. 101.\" .Pp 102.\" When the system reads the file 103.\" .Pa /etc/group 104.\" the fields are read into the structure 105.\" .Fa group 106.\" declared in 107.\" .In grp.h : 108.\" .Bd -literal -offset indent 109.\" struct group { 110.\" char *gr_name; /* group name */ 111.\" char *gr_passwd; /* group password */ 112.\" int gr_gid; /* group id */ 113.\" char **gr_mem; /* group members */ 114.\" }; 115.\" .Ed 116.Sh LIMITS 117There are various limitations which are explained in 118the function where they occur; see section 119.Sx SEE ALSO . 120.Pp 121In older implementations, 122a group cannot have more than 200 members. 123The maximum line length of 124.Pa /etc/group 125is 1024 characters. 126Longer lines will be skipped. 127This limitation disappeared in 128.Fx 3.0 . 129Older binaries that are statically linked, depend on old 130shared libraries, or 131.No non- Ns Dx 132binaries in compatibility mode 133may still have this limit. 134.Sh FILES 135.Bl -tag -width /etc/group -compact 136.It Pa /etc/group 137.El 138.Sh SEE ALSO 139.Xr passwd 1 , 140.Xr setgroups 2 , 141.Xr crypt 3 , 142.Xr getgrent 3 , 143.Xr initgroups 3 , 144.Xr nsswitch.conf 5 , 145.Xr passwd 5 , 146.Xr chkgrp 8 , 147.Xr pw 8 , 148.Xr yp 8 149.Sh HISTORY 150A 151.Nm 152file format appeared in 153.At v6 . 154Support for comments first appeared in 155.Fx 3.0 . 156.Sh BUGS 157The 158.Xr passwd 1 159command does not change the 160.Nm 161passwords. 162