old_contents: import six
  
  if six.PY2:
      import commands
      get_command_output = commands.getoutput
      get_command_status_output = commands.getstatusoutput
  
      cmp_ = cmp
  else:
      def get_command_status_output(command):
          try:
              import subprocess
              return (
                  0,
                  subprocess.check_output(
                      command,
                      shell=True,
                      universal_newlines=True))
          except subprocess.CalledProcessError as e:
              return (e.returncode, e.output)
  
      def get_command_output(command):
          return get_command_status_output(command)[1]
  
      cmp_ = lambda x, y: (x > y) - (x < y)
  
new_contents: import six
  
  if six.PY2:
      import commands
      get_command_output = commands.getoutput
      get_command_status_output = commands.getstatusoutput
  
      cmp_ = cmp
  else:
      def get_command_status_output(command):
          try:
              import subprocess
              return (
                  0,
                  subprocess.check_output(
                      command,
                      shell=True,
                      universal_newlines=True).rstrip())
          except subprocess.CalledProcessError as e:
              return (e.returncode, e.output)
  
      def get_command_output(command):
          return get_command_status_output(command)[1]
  
      cmp_ = lambda x, y: (x > y) - (x < y)
  
subject: Remove trailing characters from command output.