title: Python subprocess does not work
body: <p>I try to use a program called bwa in python with the subprocess module:
  subprocess.call('bwa', shell=True)
  Result is:
  /bin/sh: bwa: command not found
  However if I start a terminal and type the command, the program starts (i.e. I get the Usage dialogue).</p>
  
  <p>The binaries of bwa are in a folder on my desktop. In .bash_profile I have modified the path variable so that everytime I type 'bwa' in the terminal, the program binaries are found in my folder.</p>
  
  <p>My assumption is that the subprocess does not start a shell with my bash_profile settings ... but if that is correct why wouldn't it do so and what can I do about it?</p>