title: Edit multiple lines at once in Emacs
body: <p>I believe <a href="https://en.wikipedia.org/wiki/TextMate" rel="nofollow noreferrer">TextMate</a> has a mode where if you start typing, the same thing will be entered on all the lines you've selected. Is there something similar to this in Emacs?</p>
  <p>I'm guessing there's a way rectangles can help me, but I'm not sure how...</p>