update

if not fs.exists("/upd_url") then
  print("Enter filename:")
  local url = "http://immibis.com/ccfiles/" .. read()
  local c = http.get(url)
  if not c then error("failed to download "..url, 0) end
  c.close()
  local f = fs.open("/upd_url","w")
  f.write(url)
  f.close()
end

local f = fs.open("/upd_url", "r")
local url = f.readAll()
f.close()

local c = http.get(url)
if c then
 local d = c.readAll()
 c.close()
 local f = fs.open("/upd_code", "w")
 f.write(d)
 f.close()
else
 print("Download failed from "..url)
end

shell.run("/upd_code")