TOUCH(1) BSD General Commands Manual TOUCH(1)
touch -- change file access and modification times
touch [-acfhm] [-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 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 This flag has no effect; it is accepted for compatibility reasons.
-h If file is a symbolic link, access and/or modification time of the link is changed.
This option implies -c.
-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 cur-
rent 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
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.
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 speci-
fied 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.
The touch utility is expected to be a superset of the IEEE Std 1003.2 (``POSIX.2'') specifi-
A touch utility appeared in Version 7 AT&T UNIX.
A symbolic link can't be a reference file of access and/or modification time.
BSD February 22, 2011 BSD