title: ack: Escape single quotes while providing regex
body: <p>I am using ack to search for all values of width enclosed within single or double quotes.</p>
  <p>Ex: <code>width=&quot;23&quot;</code> , <code>width='420'</code></p>
  <p>RegEx Pal confirms <code>/width=(&quot;|')\d+\1/g</code> is the right regex for the job. I am however finding it difficult to supply this regex to ack.</p>
  <p><code>&lt;prompt&gt;$ ack 'width=(&quot;|\')\d+\1'</code>     &lt;--- Escaping the <code>'</code> in the regex like<code>\'</code> did not help</p>
  <p><code>&lt;prompt&gt;$ ack 'width=(&quot;|\\\')\d+\1'</code>     &lt;--- Neither did this.</p>
  <p>Any ideas?</p>