title: How to track changes on files like dropbox does?
body: <p>Anybody know how to execute methods (python) when files are modified like Dropbox and his Continuous Data Protection mechanism that can track exactly when a file is modified and sync it.</p>
  
  <p>Of course it would not be of the entire hard-disk, but a track on a specified directory.</p>
  
  <p>OBS: For Windows and Linux OS. Mac is a plus ;)</p>