price_check.rb

require 'nokogiri'
require 'open-uri'
require 'terminal-notifier'

title = 'Bitcoin Gem'
activate = 'com.googlecode.iterm2'

current_price = 0

while 1
  page = Nokogiri::HTML open('http://bitcoingem.com/')
  h2 = page.at 'h2'

  price = h2.to_s[/(\d+\.\d+)/, 1].to_f
  if price == current_price
    sleep 5
  elsif price > current_price
    TerminalNotifier.notify("Price rose from #{current_price} to #{price}", :activate => activate, :title => title)
    current_price = price
  elsif price < current_price
    TerminalNotifier.notify("Price dropped from #{current_price} to #{price}", :activate => activate, :title => title)
    current_price = price
  end
end