-- How many hours till restart happens
restartTime = 4


-- Calculate hours to seconds minus announcement times
-- then start a timer at that amount
timer = os.startTimer( (restartTime * 3600) - 600 )

-- Listen for our timer. When time is hit,
-- move on to messaging loop
while true do
  event,p1 = os.pullEvent("timer")
  if timer == p1 then
    break
  end
end

-- Announcements at periodic times
-- sleep time equals announce time minus the next announce time
commands.exec("say Server Restarting In 10 minutes")
sleep(300)
commands.exec("say Server Restarting In 5 Minutes")
sleep(240)
commands.exec("say Server Restarting In 1 Minute")
sleep(50)
commands.exec("say Server Restarting In 10 Seconds")
sleep(5)
commands.exec("say Server Restarting In 5...")
sleep(1)
commands.exec("say Server Restarting In 4...")
sleep(1)
commands.exec("say Server Restarting In 3...")
sleep(1)
commands.exec("say Server Restarting In 2...")
sleep(1)
commands.exec("say Server Restarting In 1...")
sleep(1)
commands.exec("stop")