title: Removing Lines of Text That Exist in Another File
body: <p>I’ve got two text files, each with several hundred lines. Some of the lines exist in both files, and I want to remove those so that they exist in only one of the files. Basically, I want to reduce them to get a unique set of lines. The catch is that I can’t sort them (they are stripped-down dumps of my Chromium history).</p>
  
  <p><strong>What is the easiest way to do this?</strong></p>
  
  <p>I tried WinDiff, but that gave incorrect results. I figure that I could knock together a PHP script in a while, but am hoping that there is an easier way (preferably a command-line tool).</p>