SYS_USER=$(cat /etc/passwd | while read entry; do if [ "$(echo ${entry} | cut -d: -f3)" -lt "500" ]; then echo ${entry} | cut -d: -f1 ; fi; done)
for USER in `echo $SYS_USER`; do
	if [ $(grep -c "^${USER}$" /etc/at.deny) = 0 ]; then
		echo ${USER} | tee -a /etc/at.deny &>/dev/null
	fi
done
