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. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" From: @(#)group.5 8.3 (Berkeley) 4/19/94 33.\" $FreeBSD$ 34.\" 35.Dd September 29, 1994 36.Dt GROUP 5 37.Os 38.Sh NAME 39.Nm group 40.Nd format of the group permissions file 41.Sh DESCRIPTION 42The file 43.Aq Pa /etc/group 44consists of newline separated 45.Tn ASCII 46records, one per group, containing four colon 47.Ql \&: 48separated fields. 49These fields are as follows: 50.Bl -tag -width password -offset indent -compact 51.It group 52Name of the group. 53.It passwd 54Group's 55.Em encrypted 56password. 57.It gid 58The group's decimal ID. 59.It member 60Group members. 61.El 62.Pp 63Lines whose first non-whitespace character is a pound-sign (#) 64are comments, and are ignored. 65Blank lines that consist 66only of spaces, tabs or newlines are also ignored. 67.Pp 68The 69.Ar group 70field is the group name used for granting file access to users 71who are members of the group. 72The 73.Ar gid 74field is the number associated with the group name. 75They should both be unique across the system (and often 76across a group of systems) since they control file access. 77The 78.Ar passwd 79field 80is an optional 81.Em encrypted 82password. 83This field is rarely used 84and an asterisk is normally placed in it rather than leaving it blank. 85The 86.Ar member 87field contains the names of users granted the privileges of 88.Ar group . 89The member names are separated by commas without spaces or newlines. 90A user is automatically in a group if that group was specified 91in their 92.Pa /etc/passwd 93entry and does not need to be added to that group in the 94.Pa /etc/group file. 95.\" .Pp 96.\" When the system reads the file 97.\" .Pa /etc/group 98.\" the fields are read into the structure 99.\" .Fa group 100.\" declared in 101.\" .Aq Pa grp.h : 102.\" .Bd -literal -offset indent 103.\" struct group { 104.\" char *gr_name; /* group name */ 105.\" char *gr_passwd; /* group password */ 106.\" int gr_gid; /* group id */ 107.\" char **gr_mem; /* group members */ 108.\" }; 109.\" .Ed 110.Sh YP/NIS INTERACTION 111The 112.Pa /etc/group 113file can be configured to enable the YP/NIS group database. 114An entry whose 115.Ar name 116field consists of a plus sign (`+') followed by a group name, will be 117replaced internally to the C library with the YP/NIS group entry for the 118named group. An entry whose 119.Ar name 120field consists of a single plus sign with no group name following, 121will be replaced with the entire YP/NIS 122.Dq Li group.byname 123map. 124.Pp 125If the YP/NIS group database is enabled for any reason, all reverse 126lookups (i.e., 127.Fn getgrgid ) 128will use the entire database, even if only a few groups are enabled. 129Thus, the group name returned by 130.Fn getgrgid 131is not guaranteed to have a valid forward mapping. 132.Sh LIMITS 133There are various limitations which are explained in 134the function where they occur; see section 135.Sx SEE ALSO . 136 137In older implementations, 138a group cannot have more than 200 members. 139The maximum line length of 140.Pa /etc/group 141is 1024 characters. 142Longer lines will be skipped. 143This limitation disappeared in 144.Fx 3.0 . 145Older binaries that are statically linked, depend on old 146shared libraries, or non-FreeBSD binaries in compatibility mode 147may still have this limits. 148.Sh FILES 149.Bl -tag -width /etc/group -compact 150.It Pa /etc/group 151.El 152.Sh SEE ALSO 153.Xr passwd 1 , 154.Xr setgroups 2 , 155.Xr crypt 3 , 156.Xr getgrent 3 , 157.Xr initgroups 3 , 158.Xr yp 4 , 159.Xr passwd 5 160.Sh BUGS 161The 162.Xr passwd 1 163command does not change the 164.Nm group 165passwords. 166.Sh HISTORY 167A 168.Nm 169file format appeared in 170.At v6 . 171The YP/NIS functionality is modeled after 172.Tn SunOS 173and first appeared in 174.Tn FreeBSD 1751.1. 176Support for comments first appeared in 177.Fx 3.0 . 178