TOUCH(1) BSD General Commands Manual TOUCH(1)NAMEtouch — change file access and modification times
SYNOPSIStouch [-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 ALSOutimes(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 counter‐
parts 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
