DESCRIPTION

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.

OPTIONS

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.

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.

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.

EXAMPLES

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.

AUTHOR

Written by David MacKenzie and Jim Meyering.

REPORTING BUGS

GNU coreutils online help: <https://www.gnu.org/software/coreutils/>

Report any translation bugs to <https://translationproject.org/team/>

SEE ALSO

chown(2)

Full documentation <https://www.gnu.org/software/coreutils/chown>

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

DESCRIPTION

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:

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.

RETURN VALUE

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

ERRORS

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

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

The general errors for fchown() are listed below:

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

VERSIONS

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

CONFORMING TO

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.

NOTES

EXAMPLE

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).

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

int
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]);
        exit(EXIT_FAILURE);
    }

    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) {
            perror(getpwnam);
            exit(EXIT_FAILURE);
        }

        uid = pwd−>pw_uid;
    }

    if (chown(argv[2], uid, −1) == −1) {
        perror(chown);
        exit(EXIT_FAILURE);
    }

    exit(EXIT_SUCCESS);
}

SEE ALSO

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