MC Xmas

local MSG_CODE = 'm'

-- Update this script
fs.delete( "startup-update" )
shell.run( "pastebin get DUv0cGQv startup-update" )
if fs.exists( "startup-update" ) then
  fs.delete( "startup" )
  fs.move( "startup-update", "startup" )
  print( "Startup program updated!\n" )
end

local id, msg
local lbl = os.getComputerLabel()
local rec_id = tonumber(string.sub(lbl,4,lbl:len()))
print("Listening for position: ", rec_id)
rec_id = rec_id + 1
rednet.open("top")
while true do
  id, msg = rednet.receive(nil,5)
  if (id == nil or string.sub(msg,1,1) ~= MSG_CODE) then
    -- Ignore
  elseif (string.sub(msg,rec_id,rec_id) == '1') then
    redstone.setOutput("back", true)
  else
    redstone.setOutput("back", false)
  end
end