gistfile1.txt

#!/usr/bin/env ruby
# gem install celluloid net-ping
require 'celluloid/current'
require 'net/ping'
require 'ipaddr'

class ScanWorker
  include Celluloid

  def ping(ip)
    if system("ping -c1 -W1 #{ip} >/dev/null 2>&1")
      arp = `arp #{ip} | awk '{ print $4 }'`.strip
      [ip, arp]
    end
  end
end

def network_to_ips(network)
  IPAddr.new(network).to_range.map(&:to_s)[1..-2]
end

pool = ScanWorker.pool(size: 50)
futures = network_to_ips('192.168.0.0/24').map do |ip|
  pool.future.ping(ip)
end

futures.each do |future|
  value = future.value
  p value if value
end