title: How to copy/move files without replacement
body: <p>I have a backup of all of my data in two separate places. Usually the workflow is analyzing/modifying the data in one place and then backing it up by simply copying it to the other location. As data accumulates this gets slower and slower. I was wondering if there was a way when backing up to only copy over those files that don't already exist to the new location. Selecting the newer files manually isn't possible because they are organized in a really complex scheme of directories.</p>
  
  <p>What comes to mind is when you drag and drop files between two locations and it prompts you when you find directories of the same name. Basically, I want to merge all the directories but not replace any files if they already exist in the backup location.</p>