I'm new in Linux and I want to schedule a reboot at midnight. How should I do it?


  • I'm sorry I didn't put the complete details. I want a reboot every 3rd Saturday of the month at 23:30.

  • I don't know what's wrong but I cannot find crontab. What I have is cron.d; cron.daily; cron.weekly; cron.monthly;

I'm sorry for the noob question. Pls help me. Thanks.

  • 2
    The real question is why you'd want to be doing this regularly, do you have a leaky application or something? If you're scheduling regular reboots to solve a problem then you've probably got a bigger problem... Jun 27, 2010 at 14:05
  • 1
    Do you want it to reboot every night? Jun 27, 2010 at 14:33
  • 7
    I'm not voting down, because it's sort of a policy decision (and I think nightly reboots are a bit excessive), but regularly scheduling reboots across an infrastructure are a decent way of ensuring that machines have up to date kernels and all services running are patched. I've heard a 3 month uptime limit as being a good middle ground. Jun 27, 2010 at 14:37
  • If this was a comment on the question, rather than an answer, I would upvote it. Actually I would change my mind, because the question was ambiguous about whether this was a one-time or regular thing. :)
    – intuited
    Jun 27, 2010 at 14:37
  • 5
    /etc/crontab entry like 30 23 15-21 * 6 /sbin/shutdown -r now will reboot at 23:30 on the 3rd Saturday of every month.
    – Chris S
    Jun 28, 2010 at 17:53

6 Answers 6


Type shutdown -r 0:00 and it will reboot at midnight.

If you want to reboot each night, add a cron entry using crontab -e as root to run shutdown -r each midnight

@midnight shutdown -r now
  • 4
    A time argument is mandatory, you can use now.
    – Tobu
    Jun 27, 2010 at 12:38
  • No ... if he want a one time command and want to type the command now, he should add the time !
    – radius
    Jun 27, 2010 at 12:40
  • 5
    @No, it needs a time argument such as now in the crontab line. Jun 27, 2010 at 13:16
  • Oups yes sorry, I misread Tobu comment and think he tells 0:00 was useless in the first command... I edited to correct (and Massimo answers too)
    – radius
    Jun 27, 2010 at 13:21
  • 6
    Note that issuing shutdown -r 22:00 then closing the terminal will cancel the reboot command. nohup shutdown -r 22:00 & for maintaining the reboot command after closing the terminal window.
    – a coder
    Jun 2, 2016 at 19:03

Another option is the at command, available on many Linux distributions. See the man page for more info, but the general syntax for your purpose would be:

echo "reboot" | at 0000 jun 27

To quote the OS X man page:

at - executes commands at a specified time

Sound like what we're talking about. ;)


Using crontab.


Adding this entry to /etc/crontab should do:

0 0 * * * /sbin/shutdown -r now
  • 3
    shutdown needs a time argument such as now Jun 27, 2010 at 13:19
  • 1
    This will do the reboot every night. I am not sure if this is what he wants.
    – cstamas
    Jun 27, 2010 at 14:39
  • 1
    The original question made it sound like he wanted it rebooted every night. He actually wants it rebooted every 3rd Saturday, which would still be easiest with a crontab
    – Chris S
    Jun 28, 2010 at 17:51
  • i dont know what's wrong but i cannot find the crontab..? what i have is the cron.d;cron.daily; cron.weekly; cron.monthly; I'm sorry for the noob question.Pls help me. thanks
    – klauriens
    Jun 30, 2010 at 11:00
  • It depends on the distribution you're using, but usually you should find a file called "crontab" in your system's /etc directory. You should also be able to examine the current crontab using the command "crontab -l", and to edit it using "crontab -e".
    – Massimo
    Jun 30, 2010 at 13:12

As far as I know, you cannot use cron to schedule tasks for "last Friday of each month" or "third Thursday in each month". What you can do, however ugly it seems, is to have a script run every Saturday at 23:30 and then have this script determine if this particular Saturday is the third Saturday of the week (can be done using date and maybe cal commands).

I hope this helps. I have not found an elagant solution to this problem. I found this thread, because I was searching for a solution for the same problem.

  • 3
    the comments above of "30 23 15-21 * 6 /sbin/shutdown -r now" will work. It'll basically only run on the third week of the month, but only when it's also saturday
    – Sirex
    Mar 6, 2012 at 14:47
  • I do not think this cron line works as you think it does.
    – ervingsb
    Mar 8, 2012 at 9:36
  • I created the following two lines: "30 23 1-7 * 4 date" and "30 23 1-7 * 3 date". I got two mails last night both saying: "Wed Mar 7 23:30:02 CET 2012"
    – ervingsb
    Mar 8, 2012 at 9:37
  • the last field matches the day of the week, with zero being sunday. the 4 cronjob should not have matched on a wednesday.
    – Sirex
    Mar 9, 2012 at 15:35
  • That is what I meant. The rule you wrote do not mean what you think it means. It will trigger the job every day for a week. No matter the weekday.
    – ervingsb
    Mar 9, 2012 at 19:47

1) at the command line type which reboot
2) once you know where reboot is located (usually /sbin/reboot) cd into one of the the directories in /etc/cron.daily , /etc/cron.weekly , /etc/cron.hourly etc... ie cd /etc/cron.weekly

3) create a file (using nano or vim) call it zzreboot and add the following lines:


The reason you want to call the file zzwhatever is to make sure it's the last job called after all other jobs. To make sure just do an ls -l in the directory and verify it's the last file.


I know this is an old question, still I would like to answer it. On your terminal logged in as root follow below steps:

  1. #crontab -e this would open the cron file to write your cron jobs
  2. add a new line like30 23 15-21 * sat /path/to/reboot. This cron job would reboot the system every 3rd sat of the month at 11.30 pm.
  3. save and exit

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