Sample bash script for checking unread mails in the spool.

check_mail.sh

#!/usr/bin/env bash
#
# script for checking local mail
#
#
# * for running every one hour:
#
# $ crontab -e
# 
# # m h  dom mon dow   command
# * */1 * * * /path/to/check_mail.sh

num_mails=`grep "Subject:" "/var/spool/mail/$USER" 2> /dev/null | wc -l`

if [ $num_mails -gt 0 ]; then
	echo "You've got mails"
else
	echo "No mail"
fi