title: How do you handle pipes and output in Python?
body: <p>I'm attempting to execute this command within my python script:</p>
  
  <pre><code>avprobeCommand = "avprobe -of json -show_streams {0} | grep '\"duration\"' | sed -n 1p | sed 's/ //g'".format(hiOutput)
  output = subprocess.check_output([avprobeCommand])
  </code></pre>
  
  <p>and I keep getting:</p>
  
  <pre><code>    Traceback (most recent call last):
    File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/threading.py", line 552, in __bootstrap_inner
      self.run()
    File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/threading.py", line 505, in run
      self.__target(*self.__args, **self.__kwargs)
    File "/Users/jmakaila/Documents/Development/Present/Web/video_dev/present-live-transcoder/Transcoder.py", line 60, in transcode
      output = subprocess.check_output([avprobeCommand])
    File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/subprocess.py", line 537, in check_output
      process = Popen(stdout=PIPE, *popenargs, **kwargs)
    File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/subprocess.py", line 679, in __init__
      errread, errwrite)
    File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/subprocess.py", line 1228, in _execute_child
      raise child_exception
  OSError: [Errno 2] No such file or directory
  </code></pre>
  
  <p>I've already tried splitting the args up, but I keep getting an error for the -of json -show_streams part, which, for the record, looked like this:</p>
  
  <pre><code>subprocess.check_output(["avprobe", "-of json", "-show_streams", "{0}".format(hiOutput)
  </code></pre>