Save n*bytes worth of serial input directly to file

SerialSave.rb

#!/usr/bin/ruby -wKU
require "rubygems"
require "serialport"

device = ARGV[0] ? ARGV[0] : nil
input_size = ARGV[1] ? ARGV[1] : nil
output_file = ARGV[2] ? ARGV[2] : nil

if !input_size || !output_file || !device
  Kernel.exit
end

port_str = device
baud_rate = 9600
data_bits = 8
stop_bits = 1
parity = SerialPort::NONE

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

File.open(output_file, "w") { |file| 
  while file.pos < input_size.to_i do 
    file.putc(sp.getc)
  end
}

sp.close