Shell Script for rebooting system at a particular time

#!/bin/bash
time=`date | cut -f4 -d" " | cut -f1,2 -d:`
yes=05:10
if [ "$time" = "$yes" ]
then
/sbin/reboot
else
 echo " `date` -  Not Re-booted" > /etc/motd
fi

Save file as rboot.sh and put it in /bin file. And now add the cronjob to execute the script.

# crontab -e
42 05 * * * sh /bin/rboot.sh

If the script is not executed it will display the message in motd