title: concatenate multi records in pig
body: <p>I want to concatenate all records using Pig. 
  After load in the data with "pigStorage" and '-tagFile' label, my data looks like:</p>
  
  <pre><code>(filename, aaaaaaaaaaa)
  (filename, bbbbbbbbbbbbbb)
  </code></pre>
  
  <p>And the result I prefer is:</p>
  
  <pre><code>(filename, aaaaaaaaaaabbbbbbbbbbbbbb)
  </code></pre>
  
  <p>Then I can store the data into HBase with filename as rowkey.</p>
  
  <p>Any suggestion will be appreciated.</p>