chown(1p) — Linux manual page

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.1‐2017, 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.1‐2017, 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.1‐2017, 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.1‐2017. 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.1‐2017 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.1‐2017 because the <period> is a valid character
       in login names (as specified by the Base Definitions volume of
       POSIX.1‐2017, 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.1‐2017, Chapter 8,
       Environment Variables, Section 12.2, Utility Syntax Guidelines

       The System Interfaces volume of POSIX.1‐2017, chown(3p)

COPYRIGHT         top

       Portions of this text are reprinted and reproduced in electronic
       form from IEEE Std 1003.1-2017, Standard for Information
       Technology -- Portable Operating System Interface (POSIX), The
       Open Group Base Specifications Issue 7, 2018 Edition, Copyright
       (C) 2018 by the Institute of Electrical and Electronics
       Engineers, Inc and The Open Group.  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.opengroup.org/unix/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               2017                         CHOWN(1P)

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