title: grep: write error: Broken pipe with subprocess
body: <p>I get couple of grep:write errors when I run this code. 
  What am I missing?</p>
  
  <p>This is only part of it:</p>
  
  <pre><code>     while d &lt;= datetime.datetime(year, month, daysInMonth[month]):
          day = d.strftime("%Y%m%d")
          print day
          results = [day]
          first=subprocess.Popen("grep -Eliw 'Algeria|Bahrain' "+ monthDir +"/"+day+"*.txt | grep -Eliw 'Protest|protesters' "+ monthDir +"/"+day+"*.txt", shell=True, stdout=subprocess.PIPE, )
          output1=first.communicate()[0]
          d += delta
          day = d.strftime("%Y%m%d")
          second=subprocess.Popen("grep -Eliw 'Algeria|Bahrain' "+ monthDir +"/"+day+"*.txt | grep -Eliw 'Protest|protesters' "+ monthDir +"/"+day+"*.txt", shell=True,  stdout=subprocess.PIPE, )
          output2=second.communicate()[0]
          articleList = (output1.split('\n'))
          articleList2 = (output2.split('\n'))
          results.append( len(articleList)+len(articleList2))
          w.writerow(tuple(results))
          d += delta
  </code></pre>