The chown utility will set the user ID of the file named by each file to the user ID specified by owner, and, optionally, will set the group ID to that specified by group.

If chown is invoked by other than the super-user, the set-user-ID bit is cleared.

Only the owner of a file (or the super-user) may change the owner of that file.

The operating system has a configuration option {_POSIX_CHOWN_RESTRICTED}, to restrict ownership changes. When this option is in effect the owner of the file is prevented from changing the owner ID of the file. Only the super-user can arbitrarily change owner IDs whether or not this option is in effect. To set this configuration option, include the following line in /etc/system:

set rstchown = 1

To disable this option, include the following line in /etc/system:

set rstchown = 0

{_POSIX_CHOWN_RESTRICTED} is enabled by default. See system(4) and fpathconf(2).

The following options are supported:

-f

Do not report errors.

-h

If the file is a symbolic link, change the owner of the symbolic link. Without this option, the owner of the file referenced by the symbolic link is changed.

-R

Recursive. chown descends through the directory, and any subdirectories, setting the ownership ID as it proceeds. When a symbolic link is encountered, the owner of the target file is changed (unless the -h option is specified), but no recursion takes place.

The following operands are supported:

owner[:group]

A user ID and optional group ID to be assigned to file. The owner portion of this operand must be a user name from the user database or a numeric user ID. Either specifies a user ID to be given to each file named by file. If a numeric owner exists in the user database as a user name, the user ID number associated with that user name will be used as the user ID. Similarly, if the group portion of this operand is present, it must be a group name from the group database or a numeric group ID. Either specifies a group ID to be given to each file. If a numeric group operand exists in the group database as a group name, the group ID number associated with that group name will be used as the group ID.

file

A path name of a file whose user ID is to be modified.

See largefile(5) for the description of the behavior of chown when encountering files greater than or equal to 2 Gbyte ( 2³¹ bytes).

See environ(5) for descriptions of the following environment variables that affect the execution of chown: LC_CTYPE, LC_MESSAGES, and NLSPATH.

The following exit values are returned:

0

The utility executed successfully and all requested changes were made.

>0

An error occurred.

/etc/passwd

system password file

See attributes(5) for descriptions of the following attributes:

chgrp(1), chmod(1), chown(2), fpathconf(2), passwd(4), system(4), attributes(5), environ(5), largefile(5)

chown is CSI-enabled except for the owner and group names.