track_stream.rb

require 'time'
require 'rubygems'
require 'json'

def usage
  puts <<EOS
Usage:
  ruby track_stream.rb <username> <password> <keyword1> <keyword2> ...
EOS
end

if ARGV.empty?
  usage
  exit
end

user = ARGV.shift
pass = ARGV.shift
keywords = ARGV

open("|curl -s http://stream.twitter.com/1/statuses/filter.json?track=#{keywords.join(',')} -u#{user}:#{pass}").each_line do |line|
  begin
    json = JSON.parse(line)
    created_at = Time.parse(json['created_at'])
    name = json['user']['screen_name']
    text = json['text'].gsub(/\n/, "\n" + ' ' * 32)

    printf "%s %-20s   %s\n", created_at.strftime('%H:%M:%S'), name, text
  rescue JSON::ParserError
    puts "Parse error for line #{line}"
  end
end