To create a file with a specific timestamp or update the timestamp of a file, you can use the touch command.
An example is shown below.
touch -t 201009011200 /path/to/my/file
This will create the file /path/to/my/file with the timestamp 09/01/2010 12:00.
# ls -lt /path/to/my/file
-rw-r–r– 1 root root 0 Sep 1 2010 /path/to/my/file
A timestamped file can be useful for doing things like this:
find /var ! -newer /path/to/my/file
This will find files in /var that are older than /path/to/my/file (9/1/2010).
