title: Merge multiple csv files awk column-wise, no match
body: <p>I'm sure this is a no-brainer and probably has been asked but I've been searching for ever now. So sorry for the dumb question!</p>
  
  <p>I want to merge <strong>multiple</strong> CSV files:</p>
  
  <p>File1</p>
  
  <pre><code>A, B
  A, B
  A, B
  </code></pre>
  
  <p>File2</p>
  
  <pre><code>C
  C
  C
  </code></pre>
  
  <p>File3</p>
  
  <pre><code>D
  D
  D
  </code></pre>
  
  <p>and I want to yield </p>
  
  <pre><code>A, B, C, D
  A, B, C, D
  A, B, C, D
  </code></pre>
  
  <p>I'm actually sorry for asking.
  Thanks so much you making my life easier, though. </p>