title: How do I get MKS sed to output this double quote?
body: <p>The line</p>
  
  <pre><code>echo xxx | sed "s/xxx/a""b/"
  </code></pre>
  
  <p>outputs</p>
  
  <pre><code>ab
  </code></pre>
  
  <p>rather than</p>
  
  <pre><code>a"b
  </code></pre>
  
  <p>as expected.</p>
  
  <p>What's the fix?</p>