title: matching columns from two files
body: <p>I have two files, in which the first column of them might have same values. I would like to match the first column of both files, and print the lines in FILE1 for which there was a match.</p>
  
  <pre><code>FILE1:
  xxx1 yyy yyy yyy
  xxx2 yyy yyy yyy
  xxx3 yyy yyy yyy
  
  FILE2:
  xxx3 zzzz
  xxx4 zzzz
  
  OUTPUT:
  xxx3 yyy yyy yyy
  </code></pre>
  
  <p>Any suggestions are welcomed.</p>
  
  <p>Best wishes</p>