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

NAME
       chown - change the file ownership

SYNOPSIS
       chown [-hR] owner[:group] file ...

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

DESCRIPTION
       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
       IEEE Std 1003.1-2001, 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
       The  chown  utility  shall conform to the Base Definitions volume of IEEE Std 1003.1-2001,
       Section 12.2, Utility Syntax Guidelines.

       The following options shall be supported by the implementation:

       -h     If the system supports user IDs for symbolic links,  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 the system supports group IDs for symbolic links, and 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. If the system does not sup-
	      port  user or group IDs for symbolic links, for each file operand that names a file
	      of type symbolic link, chown shall do nothing more with the current file and  shall
	      go on to any remaining files.

       -H     If the -R option is specified and a symbolic link referencing a file of type direc-
	      tory 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 direc-
	      tory 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 if the  system  supports
	      this  operation.	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 util-
       ity.

OPERANDS
       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  op-
	      erands.  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.  Simi-
	      larly,  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 data-
	      base 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
       Not used.

INPUT FILES
       None.

ENVIRONMENT VARIABLES
       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 IEEE Std 1003.1-2001, Section 8.2, Inter-
	      nationalization 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  interna-
	      tionalization 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  argu-
	      ments).

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

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

ASYNCHRONOUS EVENTS
       Default.

STDOUT
       Not used.

STDERR
       The standard error shall be used only for diagnostic messages.

OUTPUT FILES
       None.

EXTENDED DESCRIPTION
       None.

EXIT STATUS
       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
       Default.

       The following sections are informative.

APPLICATION USAGE
       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
       None.

RATIONALE
       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 unwork-
       able  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 IEEE Std 1003.1-2001. 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
       IEEE Std 1003.1-2001 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
       IEEE Std 1003.1-2001 because the period is a valid character in login names (as	specified
       by  the Base Definitions volume of IEEE Std 1003.1-2001, 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 histor-
       ical UNIX system tools approach; since a tool, find, already exists to recurse over direc-
       tories, 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  hierar-
       chy, and is in widespread historical use.

FUTURE DIRECTIONS
       None.

SEE ALSO
       chmod , chgrp , the System Interfaces volume of IEEE Std 1003.1-2001, chown()

COPYRIGHT
       Portions  of  this  text  are  reprinted  and  reproduced in electronic form from IEEE Std
       1003.1, 2003 Edition, Standard for Information Technology  --  Portable	Operating  System
       Interface  (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 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 orig-
       inal Standard can be obtained online at http://www.opengroup.org/unix/online.html .

IEEE/The Open Group			       2003					 CHOWN(P)
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