tell your current public IP using ruby

get-public-ip.rb

#!/usr/bin/ruby

# This script prints your current public IP 
#
# It retrieves it using http://checkip.dyndns.org web page.
# If given a parameter, it treats it as (float) number of seconds
# before timeout. The default timeout is set to 10 seconds.
# 
# Author: Jan Pipek (jan.pipek AT gmail.com)

require 'net/http'
require 'timeout'

# Maximum number of seconds to wait (as float)
secs_to_wait = ARGV[0].to_f || 10

begin
  Timeout::timeout(secs_to_wait) do
    response = Net::HTTP.get URI.parse('http://checkip.dyndns.org')
    puts response.match( /(?:Address: )([\d\.]+)/ )[1]
  end
rescue
  puts "Timeout: Unable to reach checkip.dyndns.org."
end