title: Find string after last underscore before dot extension
body: <p>I need to find <code>20140809T0000Z</code> in this string:</p>
  
  <pre><code>PREVIMER_F2-MARS3D-MENOR1200_20140809T0000Z.nc
  </code></pre>
  
  <p>I tried the following to keep the string before the <code>.nc</code>: </p>
  
  <pre><code>(?&lt;=_)(.*)(?=.nc) 
  </code></pre>
  
  <p>I have the following to start from the last underscore:</p>
  
  <pre><code>/_[^_]*$/
  </code></pre>
  
  <p>How can I find string after last underscore before dot extension, using a regex?</p>