title: awk - Merge two files by matching columns and append the columns values of second file to the line
body: <p>I have an unusual merge request in awk. Hoping you could help.</p>
  
  <p><strong>File1</strong></p>
  
  <pre><code>pl1,prop1,20
  
  pl1,prop2,30
  
  pl1,prop3,40
  
  pl2,prop1,70
  
  pl2,prop2,80
  
  pl2,prop3,90
  
  pl3,prop1,120
  
  pl3,prop2,130
  
  pl3,prop3,140
  </code></pre>
  
  <p><strong>File2</strong></p>
  
  <pre><code>store1,pl1
  
  store2,pl1
  
  store3,pl2
  
  store4,pl3
  
  store5,pl2
  
  store6,pl1
  </code></pre>
  
  <p><strong>Output:</strong></p>
  
  <pre><code>prop1, store1-20, store2-20, store3-70, store4-120, store5-70, store6-20
  
  prop2, store1-30, store2-30, store3-80, store4-130, store5-80, store6-30
  
  prop3, store1-40, store2-40, store3-90, store4-140, store5-90, store6-40
  </code></pre>
  
  <p><strong>Rules</strong></p>
  
  <ol>
  <li>file1.column1 should match file2.column2</li>
  <li>for all matching lines - file2.column1 should be concatenated with file1.currentLine.column3 should be appended</li>
  </ol>
  
  <p>Many thanks,</p>