title: How to execute ANT tasks on only files that have been modified
body: <p>I have a build script that does a number of things (minimize javascript, upload to amazon s3 etc). The minimize ANT task only operates on the javascript that I have modified and ignores the rest (I didn't write this script). I would like to do something similar for the amazon s3 task where only the updated content is upload in the task. Any leads on how to do this would be greatly appreciated. </p>