stream.rb

#!/usr/bin/env ruby
require "uri"
require "net/http"
require "rubygems"
require "json"

USERNAME = ''
PASSWORD = ''

uri = URI.parse('http://stream.twitter.com/1/statuses/filter.json')
Net::HTTP.start(uri.host, uri.port) do |http|
  request = Net::HTTP::Post.new(uri.request_uri)
  request.set_form_data('track' => ARGV[0])
  request.basic_auth(USERNAME, PASSWORD)
  http.request(request) do |response|
    response.read_body do |chunk|
      status = JSON.parse(chunk) rescue next
      next unless status['text']
      user = status['user']
      puts "#{user['screen_name']}: #{status['text']}"
    end
  end
end