title: Tar --exclude not working when popen(shell=False)
body: <p>I am trying to execute the following command using Popen.</p>
  
  <pre><code>args = ['/bin/tar', "--exclude='{}'".format('Build.tar.gz'), '-capvf', targetFile, '.' ]
  popen(args, stdout=subprocess.PIPE, stderr=subprocess.PIPE, universal_newlines=True)
  </code></pre>
  
  <p>However the exclude part does only work if I set shell=True IE running the above command does not exclude the file 'Build.tar.gz'. 
  Why is that?
  Is there a way to make this work without setting the shell=True ?</p>
  
  <p>regards</p>