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.\" $FreeBSD$ 30.\" 31.Dd February 8, 2013 32.Dt GROUP 5 33.Os 34.Sh NAME 35.Nm group 36.Nd format of the group permissions file 37.Sh DESCRIPTION 38The 39.Nm 40file is the local source of group information. 41It can be used in conjunction with the Hesiod domain 42`group', and the NIS maps `group.byname' and `group.bygid', 43as controlled by 44.Xr nsswitch.conf 5 . 45.Pp 46The file 47.Nm 48consists of newline separated 49.Tn ASCII 50records, one per group, containing four colon 51.Ql \&: 52separated fields. 53These fields are as follows: 54.Bl -tag -width password -offset indent -compact 55.It group 56Name of the group. 57.It passwd 58Group's 59.Em encrypted 60password. 61.It gid 62The group's decimal ID. 63.It member 64Group members. 65.El 66.Pp 67Lines whose first non-whitespace character is a pound-sign (#) 68are comments, and are ignored. 69Blank lines that consist 70only of spaces, tabs or newlines are also ignored. 71.Pp 72The 73.Ar group 74field is the group name used for granting file access to users 75who are members of the group. 76The 77.Ar gid 78field is the number associated with the group name. 79They should both be unique across the system (and often 80across a group of systems) since they control file access. 81The 82.Ar passwd 83field 84is an optional 85.Em encrypted 86password. 87This field is rarely used 88and an asterisk is normally placed in it rather than leaving it blank. 89The 90.Ar member 91field contains the names of users granted the privileges of 92.Ar group . 93The member names are separated by commas without spaces or newlines. 94A user is automatically in a group if that group was specified 95in their 96.Pa /etc/passwd 97entry and does not need to be added to that group in the 98.Nm 99file. 100.\" .Pp 101.\" When the system reads the file 102.\" .Pa /etc/group 103.\" the fields are read into the structure 104.\" .Fa group 105.\" declared in 106.\" .In grp.h : 107.\" .Bd -literal -offset indent 108.\" struct group { 109.\" char *gr_name; /* group name */ 110.\" char *gr_passwd; /* group password */ 111.\" int gr_gid; /* group id */ 112.\" char **gr_mem; /* group members */ 113.\" }; 114.\" .Ed 115.Sh IMPLEMENTATION NOTES 116The 117.Xr passwd 1 118command does not change the 119.Nm 120passwords. 121The 122.Xr pw 8 123utility's 124.Cm groupmod 125command should be used instead. 126.Sh LIMITS 127There are various limitations which are explained in 128the function where they occur; see section 129.Sx SEE ALSO . 130.Pp 131In older implementations, 132a group cannot have more than 200 members. 133The maximum line length of 134.Pa /etc/group 135is 1024 characters. 136Longer lines will be skipped. 137This limitation disappeared in 138.Fx 3.0 . 139Older binaries that are statically linked, depend on old 140shared libraries, or 141.No non- Ns Fx 142binaries in compatibility mode 143may still have this limit. 144.Sh FILES 145.Bl -tag -width /etc/group -compact 146.It Pa /etc/group 147.El 148.Sh SEE ALSO 149.Xr newgrp 1 , 150.Xr passwd 1 , 151.Xr setgroups 2 , 152.Xr crypt 3 , 153.Xr getgrent 3 , 154.Xr initgroups 3 , 155.Xr nsswitch.conf 5 , 156.Xr passwd 5 , 157.Xr chkgrp 8 , 158.Xr pw 8 , 159.Xr yp 8 160.Sh HISTORY 161A 162.Nm 163file format appeared in 164.At v6 . 165Support for comments first appeared in 166.Fx 3.0 . 167