Cron job to shutdown Ubuntu

[jcoyle]

Hi,

I realise this question has been asked / answered a thousand times, but i am having problems.

I want to set up a cron job to shutdown my ubuntu box at say 11:45 each night, so i do the following:

1. Log on as root
2.
crontab -e
** Here a get a NANO window where i add this:
3.
45 23 * * * /sbin/shutdown -h
4. i then press CTRL-O to WriteOut the file, and leave the default name as it is
5. Terminal displays
crontab: installing new crontab

When 11:45 comes, it does not shutdown or anything.

I am doing something wrong?

Any insights / help appreciated.

Thanks

Joe.

[Monotoko]

there is already a way to do this:

sudo shutdown -h 23:45
that would make it shutdown at 23:45 :)

[jcoyle]

thanks for quick response - will

sudo shutdown -h 23:45

do it every day though?

thanks

[Monotoko]

If you put it in a script and make it start at bootup, yes :)

sorry for the late reply, i went offline

[jcoyle]

hi,

how would i go about doing that? where would i need to save the file?

thanks.
J.

[marcthenarc]

I think it would be easier to use 'shutdown -h now' at the required time.

If you set a time at the end of the shutdown command, chances are, if your system is quite busy, that the cron job will start just *after* 23:45 and then issue a shutdown command that will trigger a shutdown 24 hours later (or rather 23 hours 59 minutes and a few seconds later).



# Shutdown system at 23:45 every day
45 23 * * * /sbin/shutdown -h now


You are then sure that the shutdown command will execute at 23:45 (give or take a few seconds).

[mister_p_1998]

Well my machine shuts down evey day & I do this:
sudo gedit /etc/crontab

put your command in here (it runs crontab as root)

[directcharitycontribution]

Code: 0 3 * * * /sbin/shutdown now

[aquinn]

@mister_p_1998: Excellent tip, thank you.

Here's what I did:


Open /etc/crontab:
sudo gedit /etc/crontab
Add following to end of file:


# At 23.30 every evening shutdown with 1 minute's notice
30 23 * * * root shutdown -h +1

Save and close file

If you're unsure of your crontabbing skills, you can add a simple test to /etc/crontab:


# "touch" a test file every minute
* * * * * root touch /tmp/root-crontab-test
This should create a new file called "root-crontab-test" in the /tmp directory on the first invocation, and then update the "last modified" date every minute. You can monitor this by running:

ls -l /tmp/root-crontab-testYou should see something like:

-rw-r--r-- 1 root root 0 2009-07-10 21:10 /tmp/root-crontab-test