title: zshell grep negative lookbehind
body: <p>I'm trying to play around w/ a negative lookbehind regex, but I can't seem to get it to work in my zshell.  Am I doing this wrong?</p>
  
  <blockquote>
    <p>echo "Nate or nate" | grep "(\?&lt;!N)a"</p>
  </blockquote>
  
  <p>This should match the <code>a</code> in <strong>nate</strong> but <strong><em>NOT</em></strong> the <code>a</code> in <strong>Nate</strong>...right?</p>