title: perl query using -pie
body: <p>This works:</p>
  
  <pre><code>perl -pi -e 's/abc/cba/g' hellofile
  </code></pre>
  
  <p>But this does not:</p>
  
  <pre><code>perl -pie 's/cba/abc/g' hellofile
  </code></pre>
  
  <p>In other words -pi -e works but -pie does not. Why?</p>