#simplest ruby program to read from arduino serial, 
#using the SerialPort gem
#(http://rubygems.org/gems/serialport)

require "serialport"

#params for serial port
port_str = "/dev/ttyUSB0"  #may be different for you
baud_rate = 9600
data_bits = 8
stop_bits = 1
parity = SerialPort::NONE

sp = SerialPort.new(port_str, baud_rate, data_bits, stop_bits, parity)

#just read forever
while true do
   while (i = sp.gets.chomp) do       # see note 2
      puts i
      #puts i.class #String
    end
end

sp.close                       #see note 1