TOUCH(1) BSD Reference Manual TOUCH(1)
touch - change file access and modification times
touch [-acfm] [-r file] [-t [[CC]YY]MMDDhhmm[.SS]] file ...
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-
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.
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 69 to 99, the year is set to 1969 to 1999, otherwise, the year
is set in the 21st century.
A touch command appeared in Version 7 AT&T UNIX.
The touch function is expected to be a superset of the IEEE Std1003.2
4.4BSD April 28, 1995 2