title: Calling Popen in Python on a MAC - Error can not find file
body: <p>When I try to shell out of my Python 3.51 program to run the Popen command I get the following errors.  Yet when I copy the exact string I'm passing to Popen to the Terminal command line it works fine and opens the file in Adobe Reader which is my default app for the .pdf files.</p>
  
  <p>Here is the Code:</p>
  
  <blockquote>
  <pre><code>  finalCall = r'open /Users/gbarnabic/Documents/1111/combined.pdf'
      print(finalCall)
      pid_id = subprocess.Popen(finalCall).pid
  </code></pre>
  </blockquote>
  
  <p>Here is the error:</p>
  
  <blockquote>
    <p>open /Users/gbarnabic/Documents/1111/combined.pdf
    Exception in Tkinter callback
    Traceback (most recent call last):
      File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/tkinter/<strong>init</strong>.py", line 1549, in <strong>call</strong>
        return self.func(*args)
      File "pdfcomb2.py", line 212, in change_dir
        self.openPDF(outFileName, pageNum)
      File "pdfcomb2.py", line 426, in openPDF
        subprocess.run(finalCall)
      File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/subprocess.py", line 696, in run
        with Popen(*popenargs, **kwargs) as process:
      File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/subprocess.py", line 950, in <strong>init</strong>
        restore_signals, start_new_session)
      File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/subprocess.py", line 1544, in _execute_child
        raise child_exception_type(errno_num, err_msg)
    FileNotFoundError: [Errno 2] No such file or directory: 'open /Users/gb/Documents/1111/combined.pdf'
    Georges-MBP:filepicktest gb$ open /Users/gb/Documents/1111/combined.pdf
    Georges-MBP:filepicktest gb$ </p>
  </blockquote>