LAN内の全ホストのIPアドレスとMacアドレスを取得する

macaddrs.rb

#!/usr/bin/env ruby
require 'rubygems'
require 'parallel'

ARGV.each do |arg|
  unless arg =~ /^\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}$/
    STDERR.puts %Q{invalid addr "#{arg}"}
    exit 1
  end
end

first = ARGV.shift || '192.168.0.1'
last  = ARGV.shift || first.gsub(/\d+$/, '254')
puts "check #{first} ~ #{last}"

addrs = []
first.scan(/\d+$/)[0].to_i.upto(254) do |i|
  addr = first.gsub(/\d+$/, i.to_s)
  addrs << addr
  break if addr == last
end

results = Parallel.map(addrs, :in_threads => 128){|addr|
  `ping -c 1 #{addr}`
  `arp -n #{addr}`.strip
}.select{|i|
  i =~ /[a-z\d]{1,2}:[a-z\d]{1,2}:[a-z\d]{1,2}:[a-z\d]{1,2}:[a-z\d]{1,2}:[a-z\d]{1,2}/
}.map{|i|
  {
    :mac => i.scan(/[a-z\d]{1,2}:[a-z\d]{1,2}:[a-z\d]{1,2}:[a-z\d]{1,2}:[a-z\d]{1,2}:[a-z\d]{1,2}/)[0],
    :ip => i.scan(/\d+\.\d+\.\d+.\d+/)[0]
  }
}

puts "-"*2
results.each do |res|
  puts "#{res[:ip]}\t#{res[:mac]}"
end