Nmap の結果を見やすくする

nmap.rb

#! /usr/bin/env ruby
require 'open3'

class NmapResult
  IP_ADDRESS_PATTERN = /\d+\.\d+\.\d+\.\d+/
  MAC_ADDRESS_PATTERN = /([\dA-F]{2}:){5}[\dA-F]{2}/

  attr_reader :lines

  def self.parse(stdout)
    _header, *lines, _footer = *stdout.split("\n")
    lines
      .slice_when { |_l1, l2| l2.match?(IP_ADDRESS_PATTERN) }
      .map { |partial_lines| NmapResult.new(partial_lines) }
  end

  def initialize(lines)
    @lines = lines
  end

  def ip
    lines[0][IP_ADDRESS_PATTERN]
  end

  def mac_address
    return nil unless lines[2]

    lines[2][MAC_ADDRESS_PATTERN]
  end

  def device
    return nil unless lines[2]

    lines[2][/(?<=\()[\w\s]+(?=\))/]
  end
end

stdout, _ = Open3.capture2('sudo nmap -sP 192.168.1.0/24')
results = NmapResult.parse(stdout)
results.each_with_index do |result, i|
  puts if i > 0
  puts(result.ip)
  puts("#{result.device} (#{result.mac_address})") if result.device
end