EventMachine + popen

tailer.sh

#!/bin/bash

for i in {1..1000}; do
  echo -n $i
  sleep 0.001
done

test.rb

#!/usr/bin/env ruby

require 'eventmachine'

def log *message
  p [Time.now, *message]
end

module EventMachine

  class LiveProcess < EM::Connection
    def initialize *args
      @buffer = ""
      log __method__, args
    end

    def receive_data data 
      log __method__, data
      @buffer << data
    end

    def unbind
      log __method__
    end
  end

end

EM.run {
  EM.popen "./tailer.sh", EM::LiveProcess
}