title: Counting total number of lines in final map reduce output in hadoop
body: <p>Currently my num reduce task is set to <code>job.setNumReduceTasks(100);</code></p>
  
  <p>So my final output directory is in S3 and looks like the following</p>
  
  <pre><code>/output/part-r-00000.gz
  /output/part-r-00001.gz
  ... etc
  </code></pre>
  
  <p>in order to count all the lines I have to manually download and unzip all files and go through each file to count the total lines.</p>
  
  <p>Is there a total line metric store somewhere in hadoop context?</p>