How to "cron"?

[lvbing]

my ubuntu works 7x24h,i want it reboot at midnight everyday.
i read "wiki" and do:


$ crontab -e
00 00 * * * reboot

save and reboot my ubuntu. but Nothing ever happens in this time!:(

Why? How can i do?

[stumbleUpon]

You need to be root to reboot the machine....!!

So do 'sudo su' and then 'cd' to the root directory. Edit the crontab there.