1.\" $NetBSD: group.5,v 1.14 2001/09/11 01:01:57 wiz Exp $ 2.\" 3.\" Copyright (c) 1980, 1991, 1993 4.\" The Regents of the University of California. All rights reserved. 5.\" Portions Copyright(c) 1994, Jason Downs. All rights reserved. 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 1. Redistributions of source code must retain the above copyright 11.\" notice, this list of conditions and the following disclaimer. 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice, this list of conditions and the following disclaimer in the 14.\" documentation and/or other materials provided with the distribution. 15.\" 3. All advertising materials mentioning features or use of this software 16.\" must display the following acknowledgement: 17.\" This product includes software developed by the University of 18.\" California, Berkeley and its contributors. 19.\" 4. Neither the name of the University nor the names of its contributors 20.\" may be used to endorse or promote products derived from this software 21.\" without specific prior written permission. 22.\" 23.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33.\" SUCH DAMAGE. 34.\" 35.\" @(#)group.5 8.3 (Berkeley) 4/19/94 36.\" 37.Dd November 17, 2000 38.Dt GROUP 5 39.Os 40.Sh NAME 41.Nm group 42.Nd format of the group permissions file 43.Sh DESCRIPTION 44The 45.Nm 46file 47.Pa /etc/group 48is the local source of group information. 49It can be used in conjunction with the Hesiod domain 50.Sq group , 51and the 52.Tn NIS 53maps 54.Sq group.byname 55and 56.Sq group.bygid , 57as controlled by 58.Xr nsswitch.conf 5 . 59.Pp 60The 61.Nm 62file consists of newline separated 63.Tn ASCII 64records, one per group, containing four colon 65.Ql \&: 66separated fields. 67Each line has the form: 68.Dl group:passwd:gid:[member[,member]...] 69.Pp 70These fields are as follows: 71.Bl -tag -width password -offset indent -compact 72.It Em group 73Name of the group. 74.It Em passwd 75Group's 76.Em encrypted 77password. 78.It Em gid 79The group's decimal ID. 80.It Em member 81Group members. 82.El 83.Pp 84The 85.Em group 86field is the group name used for granting file access to users 87who are members of the group. 88.Pp 89The 90.Em gid 91field is the number associated with the group name. 92They should both be unique across the system (and often 93across a group of systems) since they control file access. 94.Pp 95The 96.Em passwd 97field 98is an optional 99.Em encrypted 100password. 101This field is rarely used 102and an asterisk is normally placed in it rather than leaving it blank. 103.Pp 104The 105.Em member 106field contains the names of users granted the privileges of 107.Em group . 108The member names are separated by commas without spaces or newlines. 109A user is automatically in a group if that group was specified 110in their 111.Pa /etc/passwd 112entry and does not need to be added to that group in the 113.Pa /etc/group 114file. 115.Pp 116The group with the name 117.Dq wheel 118has a special meaning to the 119.Xr su 1 120command: if it exists and has any members, only users listed in that group 121are allowed to 122.Nm su 123to 124.Dq root . 125.Sh HESIOD SUPPORT 126If 127.Sq dns 128is specified for the 129.Sq group 130database in 131.Xr nsswitch.conf 5 , 132then 133.Nm 134lookups occur from the 135.Sq group 136Hesiod domain. 137.Sh NIS SUPPORT 138If 139.Sq nis 140is specified for the 141.Sq group 142database in 143.Xr nsswitch.conf 5 , 144then 145.Nm 146lookups occur from the 147.Sq group.byname 148and 149.Sq group.bygid 150.Tn NIS 151map. 152.Sh COMPAT SUPPORT 153If 154.Sq compat 155is specified for the 156.Sq group 157database, and either 158.Sq dns 159or 160.Sq nis 161is specified for the 162.Sq group_compat 163database in 164.Xr nsswitch.conf 5 , 165then the 166.Nm 167file may also contain lines of the format 168.Pp 169+name:*:: 170.Pp 171which causes the specified group to be included from the 172.Sq group 173Hesiod domain 174or the 175.Sq group.byname 176.Tn NIS 177map (respectively). 178.Pp 179If no group name is specified, or the plus sign 180.Pq Dq \&+ 181appears alone 182on line, all groups are included from the 183Hesiod domain or the 184.Tn NIS 185map. 186.Pp 187Hesiod or 188.Tn NIS 189compat references may appear anywhere in the file, but the single 190plus sign 191.Pq Dq \&+ 192form should be on the last line, for historical reasons. 193Only the first group with a specific name encountered, whether in the 194.Nm 195file itself, or included via Hesiod or 196.Tn NIS , 197will be used. 198.Sh FILES 199.Bl -tag -width /etc/group -compact 200.It Pa /etc/group 201.El 202.Sh SEE ALSO 203.Xr passwd 1 , 204.Xr su 1 , 205.Xr setgroups 2 , 206.Xr crypt 3 , 207.Xr initgroups 3 , 208.Xr nsswitch.conf 5 , 209.Xr passwd 5 , 210.Xr yp 8 211.Sh HISTORY 212A 213.Nm 214file format appeared in 215.At v6 . 216.Pp 217The 218.Tn NIS 219file format first appeared in SunOS. 220.Pp 221The Hesiod support first appeared in 222.Nx 1.4 . 223.Sh BUGS 224The 225.Xr passwd 1 226command does not change the 227.Nm group 228passwords. 229