title: subprocess.Popen failing in macOs High Sierra 10.13.6
body: <p>Good morning.</p>
  
  <p>I'm using the following code to generate pdf documents with LaTeX.</p>
  
  <pre><code>cmd  = ['pdflatex','-interaction','nonstopmode', name + '.tex']
  proc = subprocess.Popen(cmd, stdout = subprocess.PIPE, stderr = subprocess.PIPE)
  proc.communicate()
  </code></pre>
  
  <p>Variable name is, obviously, the name of a file previously written, and I have perfectly checked that the file exists and it's valid. However, using this code in macOs High Sierra 10.13.6 gives me the following error in the second line (<code>proc = ...</code>):</p>
  
  <pre><code>File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/subprocess.py", line 710, in __init__
  errread, errwrite)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/subprocess.py", line 1335, in _execute_child
  raise child_exception
  OSError: [Errno 2] No such file or directory
  </code></pre>
  
  <p>On the other hand, the code works perfectly in Ubuntu 16.04.</p>
  
  <p>Many thanks you in advance!</p>