gistfile1.txt

from fabric.api import *
 
@task
@runs_once
def prod():
  env.roledefs['app'] = ['web1.sc', 'web2.sc', 'web3.sc', 'web4.sc']
  env.roledefs['lb'] = ['lb1.sc', 'lb2.sc']
  env.roledefs['sql'] =  ['mysql1.sc', 'mysql2.sc']
 
@task
@runs_once
def stg():
  env.roledefs['app'] = ['web1.stg', 'web2.stg']
  env.roledefs['lb'] = ['lb1.stg']
  env.roledefs['sql'] = ['mysql1.stg']
 
@task
@runs_once
def deploy():
  for task in [web,sql]:
    execute(task)
 
 
@roles('app')
def web():
  run("hostname")
 
@roles('sql')
def sql():
  run("hostname")

What's your shell call ?