opendarwin man page for touch

TOUCH(1)						    BSD General Commands Manual 						  TOUCH(1)

NAME
     touch -- change file access and modification times

SYNOPSIS
     touch [-acfhm] [-r file] [-t [[CC]YY]MMDDhhmm[.SS]] file ...

DESCRIPTION
     The touch utility sets the modification and access times of files to the current time of day.  If the file doesn't exist, it is created with
     default permissions.

     The following options are available:

     -a      Change the access time of the file.  The modification time of the file is not changed unless the -m flag is also specified.

     -c      Do not create the file if it does not exist.  The touch utility does not treat this as an error.  No error messages are displayed and
	     the exit value is not affected.

     -f      Attempt to force the update, even if the file permissions do not currently permit it.

     -h      If the file is a symbolic link, change the times of the link itself rather than the file that the link points to.	Note that -h
	     implies -c and thus will not create any new files.

     -m      Change the modification time of the file.	The access time of the file is not changed unless the -a flag is also specified.

     -r      Use the access and modifications times from the specified file instead of the current time of day.

     -t      Change the access and modification times to the specified time.  The argument should be in the form ``[[CC]YY]MMDDhhmm[.SS]'' where
	     each pair of letters represents the following:

		   CC	   The first two digits of the year (the century).
		   YY	   The second two digits of the year.  If ``YY'' is specified, but ``CC'' is not, a value for ``YY'' between 69 and 99
			   results in a ``CC'' value of 19.  Otherwise, a ``CC'' value of 20 is used.
		   MM	   The month of the year, from 1 to 12.
		   DD	   the day of the month, from 1 to 31.
		   hh	   The hour of the day, from 0 to 23.
		   mm	   The minute of the hour, from 0 to 59.
		   SS	   The second of the minute, from 0 to 61.

	     If the ``CC'' and ``YY'' letter pairs are not specified, the values default to the current year.  If the ``SS'' letter pair is not
	     specified, the value defaults to 0.

DIAGNOSTICS
     The touch utility exits 0 on success, and >0 if an error occurs.

SEE ALSO
     utimes(2)

COMPATIBILITY
     The obsolescent form of touch, where a time format is specified as the first argument, is supported.  When no -r or -t option is specified,
     there are at least two arguments, and the first argument is a string of digits either eight or ten characters in length, the first argument
     is interpreted as a time specification of the form ``MMDDhhmm[YY]''.

     The ``MM'', ``DD'', ``hh'' and ``mm'' letter pairs are treated as their counterparts specified to the -t option.  If the ``YY'' letter pair
     is in the range 39 to 99, the year is set to 1939 to 1999, otherwise, the year is set in the 21st century.

HISTORY
     A touch utility appeared in Version 7 AT&T UNIX.

STANDARDS
     The touch utility is expected to be a superset of the IEEE Std 1003.2 (``POSIX.2'') specification.

BSD
								  April 28, 1995							       BSD