require 'open4' producer = 'ruby -e" STDOUT.sync = true; loop{sleep(rand+rand) and puts 42} " 2>/dev/null' consumer = 'ruby -e" STDOUT.sync = true; STDIN.each{|line| puts line} "' open4(producer) do |pid, i, o, e| open4.spawn consumer, 0=>o, 1=>STDOUT, :stdin_timeout => 1.4 end