count_instances.rb

#!/usr/bin/env ruby
#
require 'fog'

$access_key=""
$secret_key=""

def connection
  @connection ||= Fog::Compute.new({
    :provider => 'AWS',
    :aws_access_key_id => $access_key,
    :aws_secret_access_key => $secret_key
  })
end

puts "describe_instances"
puts connection.describe_instances.body["reservationSet"].count
puts "servers"
puts connection.servers.count