#!/usr/bin/env ruby

require 'yaml'

class SystemProfiler
  class SPHardware
    def uuid
      data.dig 'Hardware', 'Hardware Overview', 'Hardware UUID'
    end

    def data
      @command_output ||= YAML.load(`/usr/sbin/system_profiler SPHardwareDataType`)
    end
  end
end

puts SystemProfiler::SPHardware.new.uuid