Section (1) chown

Linux manual pages Section 1  


chown — change file owner and group


chown [OPTION...] [OWNER][:[GROUP]] FILE...

chown [OPTION...] −−reference=RFILE FILE...


This manual page documents the GNU version of chown. chown changes the user and/or group ownership of each given file. If only an owner (a user name or numeric user ID) is given, that user is made the owner of each given file, and the files_zsingle_quotesz_ group is not changed. If the owner is followed by a colon and a group name (or numeric group ID), with no spaces between them, the group ownership of the files is changed as well. If a colon but no group name follows the user name, that user is made the owner of the files and the group of the files is changed to that user_zsingle_quotesz_s login group. If the colon and group are given, but the owner is omitted, only the group of the files is changed; in this case, chown performs the same function as chgrp. If only a colon is given, or if the entire operand is empty, neither the owner nor the group is changed.


Change the owner and/or group of each FILE to OWNER and/or GROUP. With −−reference, change the owner and group of each FILE to those of RFILE.

−c, −−changes

like verbose but report only when a change is made

−f, −−silent, −−quiet

suppress most error messages

−v, −−verbose

output a diagnostic for every file processed


affect the referent of each symbolic link (this is the default), rather than the symbolic link itself

−h, −−no−dereference

affect symbolic links instead of any referenced file (useful only on systems that can change the ownership of a symlink)


change the owner and/or group of each file only if its current owner and/or group match those specified here. Either may be omitted, in which case a match is not required for the omitted attribute


do not treat _zsingle_quotesz_/_zsingle_quotesz_ specially (the default)


fail to operate recursively on _zsingle_quotesz_/_zsingle_quotesz_


use RFILE_zsingle_quotesz_s owner and group rather than specifying OWNER:GROUP values

−R, −−recursive

operate on files and directories recursively

The following options modify how a hierarchy is traversed when the −R option is also specified. If more than one is specified, only the final one takes effect.


if a command line argument is a symbolic link to a directory, traverse it


traverse every symbolic link to a directory encountered


do not traverse any symbolic links (default)


display this help and exit


output version information and exit

Owner is unchanged if missing. Group is unchanged if missing, but changed to login group if implied by a _zsingle_quotesz_:_zsingle_quotesz_ following a symbolic OWNER. OWNER and GROUP may be numeric as well as symbolic.


chown root /u

Change the owner of /u to root.

chown root:staff /u

Likewise, but also change its group to staff.

chown −hR root /u

Change the owner of /u and subfiles to root.


Written by David MacKenzie and Jim Meyering.


GNU coreutils online help: <>

Report any translation bugs to <>



Full documentation <>

or available locally via: info _zsingle_quotesz_(coreutils) chown invocation_zsingle_quotesz_


Copyright © 2019 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <>.

This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.

Section (2) chown

Linux manual pages Section 2  


chown, fchown, lchown, fchownat — change ownership of a file


#include <unistd.h>
int chown( const char *pathname,
  uid_t owner,
  gid_t group);
int fchown( int fd,
  uid_t owner,
  gid_t group);
int lchown( const char *pathname,
  uid_t owner,
  gid_t group);
#include <fcntl.h>            /* Definition of AT_* constants */
#include <unistd.h>
int fchownat( int dirfd,
  const char *pathname,
  uid_t owner,
  gid_t group,
  int flags);
[Note] Note
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
fchown(), lchown():
/* Since glibc 2.12:
*/ _POSIX_C_SOURCE >= 200809L || _XOPEN_SOURCE >= 500 || /* Glibc versions <= 2.19:
Since glibc 2.10:
_POSIX_C_SOURCE >= 200809L
Before glibc 2.10:


These system calls change the owner and group of a file. The chown(), fchown(), and lchown() system calls differ only in how the file is specified:

  • chown() changes the ownership of the file specified by pathname, which is dereferenced if it is a symbolic link.

  • fchown() changes the ownership of the file referred to by the open file descriptor fd.

  • lchown() is like chown(), but does not dereference symbolic links.

Only a privileged process (Linux: one with the CAP_CHOWN capability) may change the owner of a file. The owner of a file may change the group of the file to any group of which that owner is a member. A privileged process (Linux: with CAP_CHOWN) may change the group arbitrarily.

If the owner or group is specified as −1, then that ID is not changed.

When the owner or group of an executable file is changed by an unprivileged user, the S_ISUID and S_ISGID mode bits are cleared. POSIX does not specify whether this also should happen when root does the chown(); the Linux behavior depends on the kernel version, and since Linux 2.2.13, root is treated like other users. In case of a non-group-executable file (i.e., one for which the S_IXGRP bit is not set) the S_ISGID bit indicates mandatory locking, and is not cleared by a chown().

When the owner or group of an executable file is changed (by any user), all capability sets for the file are cleared.


The fchownat() system call operates in exactly the same way as chown(), except for the differences described here.

If the pathname given in pathname is relative, then it is interpreted relative to the directory referred to by the file descriptor dirfd (rather than relative to the current working directory of the calling process, as is done by chown() for a relative pathname).

If pathname is relative and dirfd is the special value AT_FDCWD, then pathname is interpreted relative to the current working directory of the calling process (like chown()).

If pathname is absolute, then dirfd is ignored.

The flags argument is a bit mask created by ORing together 0 or more of the following values;

AT_EMPTY_PATH (since Linux 2.6.39)

If pathname is an empty string, operate on the file referred to by dirfd (which may have been obtained using the open(2) O_PATH flag). In this case, dirfd can refer to any type of file, not just a directory. If dirfd is AT_FDCWD, the call operates on the current working directory. This flag is Linux-specific; define _GNU_SOURCE to obtain its definition.


If pathname is a symbolic link, do not dereference it: instead operate on the link itself, like lchown(). (By default, fchownat() dereferences symbolic links, like chown().)

See openat(2) for an explanation of the need for fchownat().


On success, zero is returned. On error, −1 is returned, and errno is set appropriately.


Depending on the filesystem, errors other than those listed below can be returned.

The more general errors for chown() are listed below.


Search permission is denied on a component of the path prefix. (See also path_resolution(7).)


pathname points outside your accessible address space.


Too many symbolic links were encountered in resolving pathname.


pathname is too long.


The file does not exist.


Insufficient kernel memory was available.


A component of the path prefix is not a directory.


The calling process did not have the required permissions (see above) to change owner and/or group.


The file is marked immutable or append-only. (See ioctl_iflags(2).)


The named file resides on a read-only filesystem.

The general errors for fchown() are listed below:


fd is not a valid open file descriptor.


A low-level I/O error occurred while modifying the inode.


See above.


See above.


See above.

The same errors that occur for chown() can also occur for fchownat(). The following additional errors can occur for fchownat():


dirfd is not a valid file descriptor.


Invalid flag specified in flags.


pathname is relative and dirfd is a file descriptor referring to a file other than a directory.


fchownat() was added to Linux in kernel 2.6.16; library support was added to glibc in version 2.4.


chown(), fchown(), lchown(): 4.4BSD, SVr4, POSIX.1-2001, POSIX.1-2008.

The 4.4BSD version can be used only by the superuser (that is, ordinary users cannot give away files).

fchownat(): POSIX.1-2008.


Ownership of new files

When a new file is created (by, for example, open(2) or mkdir(2)), its owner is made the same as the filesystem user ID of the creating process. The group of the file depends on a range of factors, including the type of filesystem, the options used to mount the filesystem, and whether or not the set-group-ID mode bit is enabled on the parent directory. If the filesystem supports the −o grpid (or, synonymously −o bsdgroups) and −o nogrpid (or, synonymously −o sysvgroups) mount(8) options, then the rules are as follows:

  • If the filesystem is mounted with −o grpid, then the group of a new file is made the same as that of the parent directory.

  • If the filesystem is mounted with −o nogrpid and the set-group-ID bit is disabled on the parent directory, then the group of a new file is made the same as the process_zsingle_quotesz_s filesystem GID.

  • If the filesystem is mounted with −o nogrpid and the set-group-ID bit is enabled on the parent directory, then the group of a new file is made the same as that of the parent directory.

As at Linux 4.12, the −o grpid and −o nogrpid mount options are supported by ext2, ext3, ext4, and XFS. Filesystems that don_zsingle_quotesz_t support these mount options follow the −o nogrpid rules.

Glibc notes

On older kernels where fchownat() is unavailable, the glibc wrapper function falls back to the use of chown() and lchown(). When pathname is a relative pathname, glibc constructs a pathname based on the symbolic link in /proc/self/fd that corresponds to the dirfd argument.


The chown() semantics are deliberately violated on NFS filesystems which have UID mapping enabled. Additionally, the semantics of all system calls which access the file contents are violated, because chown() may cause immediate access revocation on already open files. Client side caching may lead to a delay between the time where ownership have been changed to allow access for a user and the time where the file can actually be accessed by the user on other clients.

Historical details

The original Linux chown(), fchown(), and lchown() system calls supported only 16-bit user and group IDs. Subsequently, Linux 2.4 added chown32(), fchown32(), and lchown32(), supporting 32-bit IDs. The glibc chown(), fchown(), and lchown() wrapper functions transparently deal with the variations across kernel versions.

In versions of Linux prior to 2.1.81 (and distinct from 2.1.46), chown() did not follow symbolic links. Since Linux 2.1.81, chown() does follow symbolic links, and there is a new system call lchown() that does not follow symbolic links. Since Linux 2.1.86, this new call (that has the same semantics as the old chown()) has got the same syscall number, and chown() got the newly introduced number.


The following program changes the ownership of the file named in its second command-line argument to the value specified in its first command-line argument. The new owner can be specified either as a numeric user ID, or as a username (which is converted to a user ID by using getpwnam(3) to perform a lookup in the system password file).

Program source

#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

main(int argc, char *argv[])
    uid_t uid;
    struct passwd *pwd;
    char *endptr;

    if (argc != 3 || argv[1][0] == _zsingle_quotesz__zsingle_quotesz_) {
        fprintf(stderr, %s <owner> <file>
, argv[0]);

    uid = strtol(argv[1], &endptr, 10);  /* Allow a numeric string */

    if (*endptr != _zsingle_quotesz__zsingle_quotesz_) {         /* Was not pure numeric string */
        pwd = getpwnam(argv[1]);   /* Try getting UID for username */
        if (pwd == NULL) {

        uid = pwd−>pw_uid;

    if (chown(argv[2], uid, −1) == −1) {



chgrp(1), chown(1), chmod(2), flock(2), path_resolution(7), symlink(7)


This page is part of release 5.04 of the Linux man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at−pages/.

  Copyright (c) 1992 Drew Eckhardt (, March 28, 1992
and Copyright (c) 1998 Andries Brouwer (
and Copyright (c) 2006, 2007, 2008, 2014 Michael Kerrisk <>

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Modified by Michael Haardt <>
Modified 1993-07-21 by Rik Faith <>
Modified 1996-07-09 by Andries Brouwer <>
Modified 1996-11-06 by Eric S. Raymond <>
Modified 1997-05-18 by Michael Haardt <>
Modified 2004-06-23 by Michael Kerrisk <>
2007-07-08, mtk, added an example program; updated SYNOPSIS
2008-05-08, mtk, Describe rules governing ownership of new files
    (bsdgroups versus sysvgroups, and the effect of the parent
    directory_zsingle_quotesz_s set-group-ID mode bit).