how to scan ports

问题：如何scan port

ruby code：
      require 'socket'
      PORT_RANGE = 1..128
      HOST = 'baidu.com'
      TIME_TO_WAIT = 5
      sockets = PORT_RANGE.map do |port|
          socket 			= Socket.new(:INET, :STREAM)
          remote_addr = Socket.sockaddr_in(port, HOST)
          begin
              socket.connect_nonblock(remote_addr)
          rescue Errno::EINPROGRESS
          end

          socket
      end

      expiration = Time.now + TIME_TO_WAIT

      loop do
          _, writable, _ = IO.select(nil, sockets, nil, expiration - Time.now)
          break unless writable
          writable.each do |socket|
              begin
                  socket.connect_nonblock(socket.remote_address)
              rescue Errno::EISCONN
                  puts "#{ HOST }:#{ socket.remote_address.ip_port } accepts connections..."
                  sockets.delete(socket)
              rescue Errno::EINVAL
                  sockets.delete(socket)
              end
          end
      end
问题： 如何scan port

问题：如何scan port
