PROLOG | NAME | SYNOPSIS | DESCRIPTION | OPTIONS | OPERANDS | STDIN | INPUT FILES | ENVIRONMENT VARIABLES | ASYNCHRONOUS EVENTS | STDOUT | STDERR | OUTPUT FILES | EXTENDED DESCRIPTION | EXIT STATUS | CONSEQUENCES OF ERRORS | APPLICATION USAGE | EXAMPLES | RATIONALE | FUTURE DIRECTIONS | SEE ALSO | COPYRIGHT

CHOWN(1P)                 POSIX Programmer's Manual                CHOWN(1P)

PROLOG         top

       This manual page is part of the POSIX Programmer's Manual.  The Linux
       implementation of this interface may differ (consult the
       corresponding Linux manual page for details of Linux behavior), or
       the interface may not be implemented on Linux.

NAME         top

       chown — change the file ownership

SYNOPSIS         top

       chown [−h] owner[:group] file...

       chown −R [−H|−L|−P] owner[:group] file...

DESCRIPTION         top

       The chown utility shall set the user ID of the file named by each
       file operand to the user ID specified by the owner operand.

       For each file operand, or, if the −R option is used, each file
       encountered while walking the directory trees specified by the file
       operands, the chown utility shall perform actions equivalent to the
       chown() function defined in the System Interfaces volume of
       POSIX.1‐2008, called with the following arguments:

        1. The file operand shall be used as the path argument.

        2. The user ID indicated by the owner portion of the first operand
           shall be used as the owner argument.

        3. If the group portion of the first operand is given, the group ID
           indicated by it shall be used as the group argument; otherwise,
           the group ownership shall not be changed.

       Unless chown is invoked by a process with appropriate privileges, the
       set-user-ID and set-group-ID bits of a regular file shall be cleared
       upon successful completion; the set-user-ID and set-group-ID bits of
       other file types may be cleared.

OPTIONS         top

       The chown utility shall conform to the Base Definitions volume of
       POSIX.1‐2008, Section 12.2, Utility Syntax Guidelines.

       The following options shall be supported by the implementation:

       −h        For each file operand that names a file of type symbolic
                 link, chown shall attempt to set the user ID of the
                 symbolic link. If a group ID was specified, for each file
                 operand that names a file of type symbolic link, chown
                 shall attempt to set the group ID of the symbolic link.

       −H        If the −R option is specified and a symbolic link
                 referencing a file of type directory is specified on the
                 command line, chown shall change the user ID (and group ID,
                 if specified) of the directory referenced by the symbolic
                 link and all files in the file hierarchy below it.

       −L        If the −R option is specified and a symbolic link
                 referencing a file of type directory is specified on the
                 command line or encountered during the traversal of a file
                 hierarchy, chown shall change the user ID (and group ID, if
                 specified) of the directory referenced by the symbolic link
                 and all files in the file hierarchy below it.

       −P        If the −R option is specified and a symbolic link is
                 specified on the command line or encountered during the
                 traversal of a file hierarchy, chown shall change the owner
                 ID (and group ID, if specified) of the symbolic link. The
                 chown utility shall not follow the symbolic link to any
                 other part of the file hierarchy.

       −R        Recursively change file user and group IDs. For each file
                 operand that names a directory, chown shall change the user
                 ID (and group ID, if specified) of the directory and all
                 files in the file hierarchy below it. Unless a −H, −L, or
                 −P option is specified, it is unspecified which of these
                 options will be used as the default.

       Specifying more than one of the mutually-exclusive options −H, −L,
       and −P shall not be considered an error. The last option specified
       shall determine the behavior of the utility.

OPERANDS         top

       The following operands shall be supported:

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

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

STDIN         top

       Not used.

INPUT FILES         top

       None.

ENVIRONMENT VARIABLES         top

       The following environment variables shall affect the execution of
       chown:

       LANG      Provide a default value for the internationalization
                 variables that are unset or null. (See the Base Definitions
                 volume of POSIX.1‐2008, Section 8.2, Internationalization
                 Variables for the precedence of internationalization
                 variables used to determine the values of locale
                 categories.)

       LC_ALL    If set to a non-empty string value, override the values of
                 all the other internationalization variables.

       LC_CTYPE  Determine the locale for the interpretation of sequences of
                 bytes of text data as characters (for example, single-byte
                 as opposed to multi-byte characters in arguments).

       LC_MESSAGES
                 Determine the locale that should be used to affect the
                 format and contents of diagnostic messages written to
                 standard error.

       NLSPATH   Determine the location of message catalogs for the
                 processing of LC_MESSAGES.

ASYNCHRONOUS EVENTS         top

       Default.

STDOUT         top

       Not used.

STDERR         top

       The standard error shall be used only for diagnostic messages.

OUTPUT FILES         top

       None.

EXTENDED DESCRIPTION         top

       None.

EXIT STATUS         top

       The following exit values shall be returned:

        0    The utility executed successfully and all requested changes
             were made.

       >0    An error occurred.

CONSEQUENCES OF ERRORS         top

       Default.

       The following sections are informative.

APPLICATION USAGE         top

       Only the owner of a file or the user with appropriate privileges may
       change the owner or group of a file.

       Some implementations restrict the use of chown to a user with
       appropriate privileges.

EXAMPLES         top

       None.

RATIONALE         top

       The System V and BSD versions use different exit status codes. Some
       implementations used the exit status as a count of the number of
       errors that occurred; this practice is unworkable since it can
       overflow the range of valid exit status values. These are masked by
       specifying only 0 and >0 as exit values.

       The functionality of chown is described substantially through
       references to functions in the System Interfaces volume of
       POSIX.1‐2008. In this way, there is no duplication of effort required
       for describing the interactions of permissions, multiple groups, and
       so on.

       The 4.3 BSD method of specifying both owner and group was included in
       this volume of POSIX.1‐2008 because:

        *  There are cases where the desired end condition could not be
           achieved using the chgrp and chown (that only changed the user
           ID) utilities. (If the current owner is not a member of the
           desired group and the desired owner is not a member of the
           current group, the chown() function could fail unless both owner
           and group are changed at the same time.)

        *  Even if they could be changed independently, in cases where both
           are being changed, there is a 100% performance penalty caused by
           being forced to invoke both utilities.

       The BSD syntax user[.group] was changed to user[:group] in this
       volume of POSIX.1‐2008 because the <period> is a valid character in
       login names (as specified by the Base Definitions volume of
       POSIX.1‐2008, login names consist of characters in the portable
       filename character set). The <colon> character was chosen as the
       replacement for the <period> character because it would never be
       allowed as a character in a user name or group name on historical
       implementations.

       The −R option is considered by some observers as an undesirable
       departure from the historical UNIX system tools approach; since a
       tool, find, already exists to recurse over directories, there seemed
       to be no good reason to require other tools to have to duplicate that
       functionality.  However, the −R option was deemed an important user
       convenience, is far more efficient than forking a separate process
       for each element of the directory hierarchy, and is in widespread
       historical use.

FUTURE DIRECTIONS         top

       None.

SEE ALSO         top

       chgrp(1p), chmod(1p)

       The Base Definitions volume of POSIX.1‐2008, Chapter 8, Environment
       Variables, Section 12.2, Utility Syntax Guidelines

       The System Interfaces volume of POSIX.1‐2008, chown(3p)

COPYRIGHT         top

       Portions of this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1, 2013 Edition, Standard for Information
       Technology -- Portable Operating System Interface (POSIX), The Open
       Group Base Specifications Issue 7, Copyright (C) 2013 by the
       Institute of Electrical and Electronics Engineers, Inc and The Open
       Group.  (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1
       applied.) In the event of any discrepancy between this version and
       the original IEEE and The Open Group Standard, the original IEEE and
       The Open Group Standard is the referee document. The original
       Standard can be obtained online at http://www.unix.org/online.html .

       Any typographical or formatting errors that appear in this page are
       most likely to have been introduced during the conversion of the
       source files to man page format. To report such errors, see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .

IEEE/The Open Group                 2013                           CHOWN(1P)

Pages that refer to this page: chgrp(1p)