title: Read in two similar files using AWK
body: <p>Originally, I have only one file to read with some conditions. Here is the code...</p>
  
  <pre><code>awk -vid="$name" -F',' 'BEGIN{counter=0;}{if($15=="true"){counter++}}END{print id,counter}' file1
  </code></pre>
  
  <p>This code worked properly.</p>
  
  <p>But now, I have to read on 2 files. 
  The only difference between the 2 files is that file2 has 1 extra column.
  file1 has 16 columns and file2 have 17 columns. There will be an instance that a row in file1 will exist in file2(plus the extra column)</p>
  
  <p>POSSIBLE cases:</p>
  
  <ol>
  <li>a row in file1 will exist in file2(disregarding extra column)</li>
  <li>a row in file1 is different to file2</li>
  <li>a row in file1 and file2 is similar except for 15th column(<em>true or false</em> as seen in the condition in the code above).</li>
  </ol>
  
  <p>Now, my problem is that if I add file2 to the code above, like this...</p>
  
  <pre><code>awk -vid="$name" -F',' 'BEGIN{counter=0;}{if($15=="true"){counter++}}END{print id,counter}' file1 file2
  </code></pre>
  
  <p><strong>awk</strong> will count the same entry twice if that entry exists in both files.</p>
  
  <p>Question:
  Is there any way to check the duplication aside from merging file1 and file2?</p>