old_contents: #!/usr/bin/env python
  
  from __future__ import division, print_function
  from subprocess import call
  import os
  import sys
  
  
  if not os.path.isfile("cactus.log"):
      if not os.path.isdir("results"):
          os.mkdir("results")
      os.chdir("results")
      call("cactus ../config/RM2.in | tee ../cactus.log", shell=True)
      call("pwd")
  else:
      sys.exit("Simulation results present; use ./clean.sh to remove")
  
new_contents: #!/usr/bin/env python
  
  from __future__ import division, print_function
  from subprocess import call
  import os
  import sys
  
  
  if not os.path.isfile("cactus.log"):
      if not os.path.isdir("results"):
          os.mkdir("results")
      os.chdir("results")
      call("cactus ../config/RM2.in | tee ../cactus.log", shell=True)
  else:
      sys.exit("Simulation results present; use ./clean.sh to remove")
  
subject: Remove unnecessary call