init.lua

component.getPrimary = function(c) return component.proxy(component.list(c)()) end

local gpu = component.getPrimary("gpu")

gpu.set(1, 1, "dong")
local w, h = gpu.getResolution()

function print(text)
  gpu.copy(1, 2, w, h-1, 0, -1)
  gpu.fill(1, h, w, 1, " ")
  gpu.set(1, h, tostring(text))
end

while true do
  computer.pullSignal(1)
  print(computer.uptime())
end