Add the below line (with tweaks) to the end of /etc/crontab:

30 23 * * * root shutdown -h now

At 23:30 (11:30 PM), the kiosk will shut down. No matter what user is logged in, the shutdown command runs as root.

(If you don't want to use the global crontab, log in as root and use crontab -e. Use the same above syntax without the root).

Cron Format:

MM HH DD OO WW command

MM: Minute, 0-59
HH: 24-hour hour
DD: Day of month
OO: Month
WW: Day of Week (Sunday is 0, Monday is 1)
command: Self-explanatory

如在22：00自动关机：

    * * *   root    shutdown -h now