is_port_open.rb

#!/usr/bin/env ruby



# $ netcat $HOST $PORT -w 1 -q 0 </dev/null && do_something

require 'socket'
require 'timeout'

def is_port_open?(ip,port)
  begin
    Timeout::timeout(1) do
      begin
        s = TCPSocket.new(ip,port)
        s.close
        return true
      rescue Errno::ECONNREFUSED, Errno::EHOSTUNREACH
        return false  
      end
    end
  rescue Timeout::Error
  end
  return false
end


host = ARGV[0].split(":")[0]
ip = ARGV[0].split(":")[1].to_i

puts is_port_open?(host,ip)