How to change the attributes of a file in linux

I often want to change the timestamp of files when testing scripts so I can see whether the logic works with different ages of files etc.

use touch:

touch -a -m -t 201512180130.09 myfile

-a  change the access time
-m change the modification time
-t STAMP use [[CC]YY]MMDDhhmm[.ss] instead of current time