.\"	$OpenBSD: chown.8,v 1.24 2024/08/01 14:44:34 jmc Exp $
.\"
.\" Copyright (c) 1990, 1991, 1993, 1994
.\"	The Regents of the University of California.  All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. Neither the name of the University nor the names of its contributors
.\"    may be used to endorse or promote products derived from this software
.\"    without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\"     from: @(#)chown.8	8.3 (Berkeley) 3/31/94
.\"
.Dd $Mdocdate: August 1 2024 $
.Dt CHOWN 8
.Os
.Sh NAME
.Nm chown
.Nd change file owner and group
.Sh SYNOPSIS
.Nm chown
.Op Fl h
.Oo
.Fl R
.Op Fl H | L | P
.Oc
.Ar owner Ns Op : Ns Ar group
.Ar
.Nm chown
.Op Fl h
.Oo
.Fl R
.Op Fl H | L | P
.Oc
.Pf : Ar group
.Ar
.Sh DESCRIPTION
.Nm
sets the user ID and/or the group ID of the specified files.
.Pp
The options are as follows:
.Bl -tag -width Ds
.It Fl H
If the
.Fl R
option is specified, symbolic links on the command line are followed.
Symbolic links encountered in the tree traversal are not followed.
.It Fl h
Treat symbolic links like other files: modify links instead of
following them.
The
.Fl h
and
.Fl R
options are mutually exclusive.
.It Fl L
If the
.Fl R
option is specified, all symbolic links are followed.
.It Fl P
If the
.Fl R
option is specified, no symbolic links are followed.
.It Fl R
Recurse.
Where
.Ar file
is a directory,
change the user ID and/or the group ID of the directory
and all the files and directories in the file hierarchy below it.
.El
.Pp
The
.Fl H ,
.Fl L ,
and
.Fl P
options are ignored unless the
.Fl R
option is specified;
if none of them are given,
the default is to not follow symbolic links.
In addition, these options override each other and the
command's actions are determined by the last one specified.
.Pp
The
.Ar owner
and
.Ar group
operands are both optional; however, one must be specified.
If the
.Ar group
operand is specified, it must be preceded by a colon
.Pq Sq \&:
character.
.Pp
The
.Ar owner
may be either a numeric user ID or a user name.
If a user name is also a numeric user ID, the operand is used as a
user name.
The
.Ar group
may be either a numeric group ID or a group name.
If a group name is also a numeric group ID, the operand is used as a
group name.
.Pp
By default,
.Nm
clears the set-user-ID and set-group-ID bits on the file
to prevent accidental or mischievous creation of
set-user-ID and set-group-ID programs.
This behaviour can be overridden by setting the
.Xr sysctl 8
variable
.Va fs.posix.setuid
to zero.
.Pp
Only the superuser is permitted to change the owner of a file.
.Sh EXIT STATUS
.Ex -std chown
.Sh SEE ALSO
.Xr chgrp 1 ,
.Xr find 1 ,
.Xr chown 2 ,
.Xr fts_open 3 ,
.Xr symlink 7
.Sh STANDARDS
The
.Nm
utility is compliant with the
.St -p1003.1-2024
specification.
.Pp
The ability to specify
.Ar group
without
.Ar owner
is an extension to that specification.
.Pp
Some
.Pf non- Bx
systems may allow the (non-privileged) owner of a file to change
its ownership.
.Pp
Previous versions of the
.Nm
utility used the dot
.Pq Sq \&.
character to distinguish the group name.
This was changed when the utility was first standardised in
.St -p1003.2-92
to be a colon
.Pq Sq \&:
character to allow user and group names to contain the dot
character, though the dot separator still remains supported
due to widely required backwards compatibility.
.Sh HISTORY
A
.Nm
command appeared in
.At v1 .