# File lib/macaddr.rb, line 59
    def address
      return @mac_address if defined? @mac_address and @mac_address

      @mac_address = from_getifaddrs
      return @mac_address if @mac_address

      cmds = '/sbin/ifconfig', '/bin/ifconfig', 'ifconfig', 'ipconfig /all', 'cat /sys/class/net/*/address'

      output = nil
      cmds.each do |cmd|
        _, stdout, _ = systemu(cmd) rescue next
        next unless stdout and stdout.size > 0
        output = stdout and break
      end
      raise "all of #{ cmds.join ' ' } failed" unless output

      @mac_address = parse(output)
    end