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