title: cannot open files in beyond compare using python
body: <p>I am making use of Beyond Compare 3 to see the difference between two XML files. I am willing to make a small python script which on executing will open files ready to compare in Beyond Compare tool. </p>
  
  <p>So far I tried invoking BC3 from command line syntax as below and it works:</p>
  
  <pre><code>BCompare.exe "c:\Ref-2.xml"  "c:\Cop-2.xml"
  </code></pre>
  
  <p>but when I try to execute same syntax from python script as shown below, It throws error</p>
  
  <pre><code>from subprocess import check_output
  check_output('BCompare.exe "c:\Ref-2.xml"  "c:\Cop-2.xml"', shell=True)
  </code></pre>
  
  <p>The error which is shown is:</p>
  
  <pre><code>raise CalledProcessError(retcode, cmd, output=output)
  subprocess.CalledProcessError: Command 'BCompare.exe "c:\Ref-2.xml"  "c:\Cop-2.xml"' returned non-zero exit status 1
  </code></pre>
  
  <p>am I missing something? I tried different solutions to open command line instructions using <a href="https://stackoverflow.com/questions/14894993/running-windows-shell-commands-with-python">this</a> tutorial and many others but its not working. </p>