title: Building a csv file from multiple files
body: <p>I have on a folder multiple txt file containing one or several lines. Each file name is an email address containing different email(s) address(es) inside.</p>
  
  <p>For example, I have 3 files on my folder :</p>
  
  <ul>
  <li>distribution-list1@example.com.txt</li>
  <li>distribution-list2@example.com.txt</li>
  <li>distribution-list3@example.com.txt</li>
  </ul>
  
  <p>Content of each files:</p>
  
  <pre><code>cat distribution-list1@example.com.txt
  john@example.com
  aurel@example.com
  
  cat distribution-list2@example.com.txt
  doe@example.com
  
  cat distribution-list3@example.com.txt
  jack@example.com
  gilbert@example.com
  jane@example.com
  </code></pre>
  
  <p>I would like to build only one file containing those data:</p>
  
  <pre><code>distribution-list1@example.com;john@example.com
  distribution-list1@example.com;aurel@example.com
  distribution-list2@example.com;doe@example.com
  distribution-list3@example.com;jack@example.com
  distribution-list3@example.com;gilbert@example.com
  distribution-list3@example.com;jane@example.com
  </code></pre>