title: Subprocess cp returns error - bufsize must be integer
body: <p>I'm trying to copy from one directory to another, and rename them at the same time by calling 'cp' like so:</p>
  
  <pre><code>directories = ['/Users/Me/Folder1/File1.txt', '/Users/Me/Folder/File2.txt']
  output = ['/Users/Me/Folder2/Hello.txt', 'Users/Me/Folder2/World.txt'] 
  for in, out, in zip(directories, output):
      subprocess.call('cp', in, out)
  </code></pre>
  
  <p>But it returns:</p>
  
  <pre><code> File "./test.py", line 33, in &lt;module&gt;
      subprocess.call('cp', in, out)
    File "/usr/local/Cellar/python/2.7.10_2/Frameworks/Python.framework/Versions/2.7/lib/python2.7/subprocess.py", line 522, in call
      return Popen(*popenargs, **kwargs).wait()
    File "/usr/local/Cellar/python/2.7.10_2/Frameworks/Python.framework/Versions/2.7/lib/python2.7/subprocess.py", line 659, in __init__
      raise TypeError("bufsize must be an integer")
  TypeError: bufsize must be an integer
  </code></pre>
  
  <p>What am I doing wrong?</p>