title: Why does Vim save files with a ~ extension?
body: <p>I've found that while using Vim on Windows Vim saves the file, a <code>.ext.swp</code> file that's deleted on closing the Vim window and a <code>.ext~</code> file. </p>
  
  <p>I assume the <code>.ext.swp</code> file is a session backup in case Vim crashes. What's the purpose of the <code>.ext~</code> file however? Is this a permanent backup file? It's annoying as I'd like to copy all the files I'm working on to my host, without these duplicates. <strong>How can I turn this off or</strong>, if it's there for a good reason, <strong>hide the files</strong>?</p>