print(wifi.sta.getip())
    --0.0.0.0
    wifi.setmode(wifi.STATION)
    wifi.sta.config("SSID","password")
    print(wifi.sta.getip())
    --192.168.18.110

    pin = 1
    gpio.mode(pin,gpio.OUTPUT)
    gpio.write(pin,gpio.HIGH)
    print(gpio.read(pin))

    -- A simple http client
    conn=net.createConnection(net.TCP, 0) 
    conn:on("receive", function(conn, payload) print(c) end )
    conn:connect(80,"115.239.210.27")
    conn:send("GET / HTTP/1.1\r\nHost: www.baidu.com\r\n"
        .."Connection: keep-alive\r\nAccept: */*\r\n\r\n")

    -- A simple http server
    srv=net.createServer(net.TCP) 
    srv:listen(80,function(conn) 
      conn:on("receive",function(conn,payload) 
        print(payload) 
        conn:send("<h1> Hello, NodeMcu.</h1>")
      end) 
    end)

  function led(r,g,b) 
    pwm.setduty(0,r) 
    pwm.setduty(1,g) 
    pwm.setduty(2,b) 
  end
  pwm.setup(0,500,50) 
  pwm.setup(1,500,50) 
  pwm.setup(2,500,50)
  pwm.start(0) 
  pwm.start(1) 
  pwm.start(2)
  led(50,0,0) -- red
  led(0,0,50) -- blue

  lighton=0
  tmr.alarm(1000,1,function()
    if lighton==0 then 
      lighton=1 
      led(50,50,50) 
    else 
      lighton=0 
      led(0,0,0) 
    end 
  end)

  --init.lua will be excuted
  file.open("init.lua","w")
  file.writeline([[print("Hello, do this at the beginning.")]])
  file.close()
  node.restart()  -- this will restart the module.

    -- a simple telnet server
    s=net.createServer(net.TCP) 
    s:listen(2323,function(c) 
       con_std = c 
       function s_output(str) 
          if(con_std~=nil) 
             then con_std:send(str) 
          end 
       end 
       node.output(s_output, 0)   -- re-direct output to function s_ouput.
       c:on("receive",function(c,l) 
          node.input(l)           -- works like pcall(loadstring(l)) but support multiple separate line
       end) 
       c:on("disconnection",function(c) 
          con_std = nil 
          node.output(nil)        -- un-regist the redirect output function, output goes to serial
       end) 
    end)