title: Why subprocess.Popen doesn't work when args is sequence?
body: <p>I'm having a problem with subprocess.Popen when args parameter is given as sequence.</p>
  
  <p>For example:</p>
  
  <pre><code>import subprocess
  maildir = "/home/support/Maildir"
  </code></pre>
  
  <p>This works (it prints the correct size of /home/support/Maildir dir):</p>
  
  <pre><code>size = subprocess.Popen(["du -s -b " + maildir], shell=True,
                          stdout=subprocess.PIPE).communicate()[0].split()[0]
  print size
  </code></pre>
  
  <p>But, this doesn't work (try it):</p>
  
  <pre><code>size = subprocess.Popen(["du", "-s -b", maildir], shell=True,
                          stdout=subprocess.PIPE).communicate()[0].split()[0]
  print size
  </code></pre>
  
  <p>What's wrong?</p>