new_contents: #!/usr/bin/env python2
  
  def is_this_chef():
      from socket import gethostname
      return gethostname() == 'chef.compbio.ucsf.edu'
  
  def require_chef():
      if not is_this_chef():
          raise SystemExit("This script must be run on chef.")
  
  
subject: Add a function to say whether or not chef is the current host.