irc in lua for the esp8266 with nodemcu -- https://github.com/nodemcu/nodemcu-firmware

init.lua

function connect_callback(conn)
    conn:send("NICK esp8266_hacklab\r\n")
    conn:send("USER esp8266_hacklab 8 * :Heeelloooo\r\n")
    conn:send("JOIN #lugola\r\n")
    conn:send("PRIVMSG #lugola :здраво свет\r\n")
end

function receive_callback(conn, payload)
  print(payload)
  if string.find(payload, "PING :") == 1 then
    conn:send("PONG :" .. string.sub(payload, 7))
  end
end

function startbot()
    local conn
    conn = net.createConnection(net.TCP, false)
    conn:on("receive", receive_callback)
    conn:on("connection", connect_callback)
    conn:connect(6667, "chat.freenode.net")
end

tmr.alarm(1, 1000, 1, function()
    if wifi.sta.getip()==nil then
        print("Waiting for connection...")
    else
        tmr.stop(1) -- maybe only stop it on successfull connection
        startbot()
    end
end)

upload-init-lua.py

#! /usr/bin/env python3
# very crude python3 script to upload an init.lua file to an esp8266 with nodemcu
# uses pyserial and uses my BusPirate(v4) in transparent UART mode
# (the only USB to TTL-UART that gave stable 3.3V power)
#
# the trick is to write commands to the nodemcu repl slowly since it can't handle it faster
# and replace the line separators in the unix file with \r when sending over serial

import sys, time
import serial

fp = open(sys.argv[1], 'rb')
ser = serial.Serial('/dev/bus-pirate', baudrate=9600)

for cmd in [b'file.open("init.lua","w")', b'file.writeline([[']:
    ser.write(cmd + b'\r\n')
    time.sleep(0.3) # can't do it faster

for line in fp:
    ser.write(line.rstrip() + b'\r')
    time.sleep(0.3) # can't do it faster

for cmd in [b']])', b'file.close()', b'node.restart()']:
    ser.write(cmd + b'\r\n')
    time.sleep(0.3) # can't do it faster

ser.close()
fp.close()

x-repl-commands.lua

-- once the init.lua file is there, enter commands in the repl to connect to the wifi
-- the esp8266 will remember these settings and always connect automatically
wifi.setmode(wifi.STATION)
wifi.station.autoconnect(1)
wifi.sta.config("KIKA", "sz123456")
node.restart()