Computercraft Timer!

print("How long do you want the timer to be?")
time = tonumber(read())
if time <= 0 then
 print("Error, Time cannot be 0")
 os.sleep(5)
 shell.run('clear')
else
 print("Starting timer")
 os.sleep(2)
 repeat
  shell.run('clear')
  print("                                       ")
  print("                                       ")
  print("                                       ")
  print("=======================================")
  print("---------------------------------------")
  print("                  "..time.."             ")
  print("---------------------------------------")
  print("    Press Ctrl+T to stop the timer")
  print("---------------------------------------")
  print("=======================================")
  os.sleep(1)
  time = time - 1
 until time == 0
 i = 0
 repeat
  print("Timer Done!")
  os.sleep(0.3)
  shell.run('clear')
  os.sleep(0.3)
  i = i + 1
 until i == 5
end