TOUCH(1)                     UNIX Reference Manual                    TOUCH(1)

NAME

     touch - change file access and modification times

SYNOPSIS

     touch [-acfm] [-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 de-
     fault 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.

     -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 ``YY'' value of 19.
                           Otherwise, a ``YY'' 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 val-
             ues default to the current year.  If the ``SS'' letter pair is
             not specified, the value defaults to 0.

     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,
     is set in the 21st century.

HISTORY

     A touch command appeared in Version 7 AT&T UNIX.

STANDARDS

     The touch function is expected to be a superset of the IEEE Std1003.2
     (``POSIX'') specification.

BSD Experimental                 March 6, 1993                               2