title: Perl regex to replace part of one string with a portion of another
body: <p>I have a need in Perl to replace a section of one string with <em>most</em> of another. :-)  This needs be done for multiple pairs of strings.</p>
  
  <p>For example, I need to replace</p>
  
  <pre><code>"/root_vdm_2/fs_clsnymigration"
  </code></pre>
  
  <p>within</p>
  
  <pre><code>/root_vdm_2/fs_clsnymigration/CLSNYMIGRATION/NY_HQ_S1
  </code></pre>
  
  <p>with </p>
  
  <pre><code>rfsn_clsnymigration
  </code></pre>
  
  <p>so that I end up with </p>
  
  <pre><code>/rfsn_clsnymigration/CLSNYMIGRATION/NY_HQ_S1
  </code></pre>
  
  <p>(without the leading "/root_vdm_2" part) ... but I am sufficiently sleep-deprived to have lost sight of how to accomplish this.</p>
  
  <p>Help ?</p>