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.Dd February 8, 2013 29.Dt GROUP 5 30.Os 31.Sh NAME 32.Nm group 33.Nd format of the group permissions file 34.Sh DESCRIPTION 35The 36.Nm 37file is the local source of group information. 38It can be used in conjunction with the Hesiod domain 39`group', and the NIS maps `group.byname' and `group.bygid', 40as controlled by 41.Xr nsswitch.conf 5 . 42.Pp 43The file 44.Nm 45consists of newline separated 46.Tn ASCII 47records, one per group, containing four colon 48.Ql \&: 49separated fields. 50These fields are as follows: 51.Bl -tag -width password -offset indent -compact 52.It group 53Name of the group. 54.It passwd 55Group's 56.Em encrypted 57password. 58.It gid 59The group's decimal ID. 60.It member 61Group members. 62.El 63.Pp 64Lines whose first non-whitespace character is a pound-sign (#) 65are comments, and are ignored. 66Blank lines that consist 67only of spaces, tabs or newlines are also ignored. 68.Pp 69The 70.Ar group 71field is the group name used for granting file access to users 72who are members of the group. 73The 74.Ar gid 75field is the number associated with the group name. 76They should both be unique across the system (and often 77across a group of systems) since they control file access. 78The 79.Ar passwd 80field 81is an optional 82.Em encrypted 83password. 84This field is rarely used 85and an asterisk is normally placed in it rather than leaving it blank. 86The 87.Ar member 88field contains the names of users granted the privileges of 89.Ar group . 90The member names are separated by commas without spaces or newlines. 91A user is automatically in a group if that group was specified 92in their 93.Pa /etc/passwd 94entry and does not need to be added to that group in the 95.Nm 96file. 97.\" .Pp 98.\" When the system reads the file 99.\" .Pa /etc/group 100.\" the fields are read into the structure 101.\" .Fa group 102.\" declared in 103.\" .In grp.h : 104.\" .Bd -literal -offset indent 105.\" struct group { 106.\" char *gr_name; /* group name */ 107.\" char *gr_passwd; /* group password */ 108.\" int gr_gid; /* group id */ 109.\" char **gr_mem; /* group members */ 110.\" }; 111.\" .Ed 112.Sh IMPLEMENTATION NOTES 113The 114.Xr passwd 1 115command does not change the 116.Nm 117passwords. 118The 119.Xr pw 8 120utility's 121.Cm groupmod 122command should be used instead. 123.Sh LIMITS 124There are various limitations which are explained in 125the function where they occur; see section 126.Sx SEE ALSO . 127.Pp 128In older implementations, 129a group cannot have more than 200 members. 130The maximum line length of 131.Pa /etc/group 132is 1024 characters. 133Longer lines will be skipped. 134This limitation disappeared in 135.Fx 3.0 . 136Older binaries that are statically linked, depend on old 137shared libraries, or 138.No non- Ns Fx 139binaries in compatibility mode 140may still have this limit. 141.Sh FILES 142.Bl -tag -width /etc/group -compact 143.It Pa /etc/group 144.El 145.Sh SEE ALSO 146.Xr newgrp 1 , 147.Xr passwd 1 , 148.Xr setgroups 2 , 149.Xr crypt 3 , 150.Xr getgrent 3 , 151.Xr initgroups 3 , 152.Xr nsswitch.conf 5 , 153.Xr passwd 5 , 154.Xr chkgrp 8 , 155.Xr pw 8 , 156.Xr yp 8 157.Sh HISTORY 158A 159.Nm 160file format appeared in 161.At v6 . 162Support for comments first appeared in 163.Fx 3.0 . 164