old_contents: from fabric.api import *
  
  env.user='%SLICE%'
  env.key_filename='~/.ssh/%SLICE%.pem'
  env.hosts = [
      'pc3.instageni.rnoc.gatech.edu',
      'pc32.utahddc.geniracks.net',
      'pc5.geni.it.cornell.edu',
      ]
  
  slivers = [
  	{'host': 'pc3.instageni.rnoc.gatech.edu', 'addr': '10.128.234.1'}, 
  	{'host': 'pc32.utahddc.geniracks.net', 'addr': '10.128.234.2'}, 
  	{'host': 'pc5.geni.it.cornell.edu', 'addr': '10.128.234.3'},
  	]
  
  
  # Install the 'nmap' RPM on all hosts
  @task
  def prepare():
      run("sudo yum -qy install nmap")
  
  # Run 'nmap' on the private network on each host.
  # See what other hosts are reachable at L2 on the private net.
  @task
  def nmap():
      run("echo My IP addresses:")
      run("ifconfig | grep -Eo 'inet (addr:)?([0-9]*\.){3}[0-9]*' | grep -Eo '([0-9]*\.){3}[0-9]*' | grep -v '127.0.0.1'")
      run("echo")
      run("echo Hosts reachable on the private subnet:")
      run("nmap -sP 10.128.234.0/24")
  
  # Your experiment script goes here...
  @task
  def run_expt():
      # run('curl http://66.92.233.109:8080/host')
      # run('ifconfig -a | grep  inet | grep :10')
      # put the commands you want to run here...
      pass
  
new_contents: from fabric.api import *
  
  env.user='%SLICE%'
  env.key_filename='~/.ssh/%SLICE%.pem'
  env.hosts = %HOSTS%
  slivers = %SLIVERS%
  
  # Install the 'nmap' RPM on all hosts
  @task
  def prepare():
      run("sudo yum -qy install nmap")
  
  # Run 'nmap' on the private network on each host.
  # See what other hosts are reachable at L2 on the private net.
  @task
  def nmap():
      run("echo My IP addresses:")
      run("ifconfig | grep -Eo 'inet (addr:)?([0-9]*\.){3}[0-9]*' | grep -Eo '([0-9]*\.){3}[0-9]*' | grep -v '127.0.0.1'")
      run("echo")
      run("echo Hosts reachable on the private subnet:")
      run("nmap -sP 10.128.234.0/24")
  
  # Your experiment script goes here...
  @task
  def run_expt():
      # run('curl http://66.92.233.109:8080/host')
      # run('ifconfig -a | grep  inet | grep :10')
      # put the commands you want to run here...
      pass
  
subject: Customize the fabfile more