title: regex to extract the number from string
body: <p>I have a string like this</p>
  
  <pre><code>file-myfle_20130207_094852am.csv
  </code></pre>
  
  <p>how do i go about writing the regex to extract only the numbers </p>
  
  <pre><code>20130207094852
  </code></pre>