touch - change file timestamps
touch [OPTION]... FILE...
Update the access and modification times of each FILE to the current time. A FILE argument that does not exist is created empty, unless -c or -h is supplied.
A FILE argument string of - is handled specially and causes touch to change the times of the file associated with standard output.
Mandatory arguments to long options are mandatory for short options too.
-a change only the access time
-c, --no-create do not create any files
-d, --date=STRING parse STRING and use it instead of current time
-h, --no-dereference affect each symbolic link instead of any referenced file (useful only on systems that can change the timestamps of a symlink)
-m change only the modification time
-r, --reference=FILE use this file’s times instead of current time
-t STAMP use [[CC]YY]MMDDhhmm[.ss] instead of current time
--time=WORD change the specified time: WORD is access, atime, or use: equivalent to -a WORD is modify or mtime: equivalent to –m
--help display this help and exit
--version output version information and exit
Note that the -d and -t options accept different time-date formats.
The --date=STRING is a mostly free format human readable date string such as "Sun, 29 Feb 2004 16:21:42 -0800" or "2004-02-29 16:21:42" or even "next Thursday". A date string may contain items indicating calendar date, time of day, time zone, day of week, relative time, relative date, and numbers. An empty string indicates the beginning of the day. The date string format is more complex than is easily documented here but is fully described in the info documentation.