PIN Program w/ MOTD

#!/bin/lua

--[[
Credit to the following people on the IRC room:
Kodos
NotLyra
Sandra
As well as the following tools:
Pastebin
I would not be able to make this program without them. I,
Ekoserin, am a Lua noob and I'm proud!
I'm a Lua noob and I'm proud!
I'm a Lua noob and I'm proud!
--]]

local component = require("component") -- We need components.
local computer = require("computer") -- We need the computer, obviously.
local text = require("text") -- We need text displaying.
local unicode = require("unicode") -- To display text, we need Unicode.
local term = require("term") -- We need "term" commands.
local pin = "1234" -- The PIN is this number.

if not component.isAvailable("gpu") then -- If GPU is not available, return.
  return
end
local lines = {_OSVERSION .. " (" .. math.floor(computer.totalMemory() / 1024) .. "k RAM)"}
local maxWidth = unicode.len(lines[1])
local f = io.open("/usr/misc/greetings2.txt") -- Open greetings2.txt
if f then
  local greetings = {}
  pcall(function()
    for line in f:lines() do table.insert(greetings, line) end
  end)
  f:close()
  local greeting = greetings[math.random(1, #greetings)]
  if greeting then
    local width = math.max(10, component.gpu.getResolution())
    for line in text.wrappedLines(greeting, width - 4, width - 4) do
      table.insert(lines, line)
      maxWidth = math.max(maxWidth, unicode.len(line))
    end
  end
end

::pin_enter::
print("Please enter the correct PIN to unlock door.") -- Display text.
local inputvar = text.trim(term.read())
if inputvar == pin then -- If input is equal to the PIN, goto "correct"
  goto correct
else
  print("Incorrect.") -- Display text.
  goto pin_enter -- Goto "pin_enter"
end
::correct::
print("Correct.")