nagios-plugins/check_nagios/check_nagios_ghostservices

#!/bin/sh
TMP=`mktemp`
LAST_HOUR=`date "+%b %e %H:" -d "1 hour ago"`
CURRENT_HOUR=`date "+%b %e %H:"`

exit_unknown() {
	msg="$1"

	echo "${msg}"
	exit 3
}

find_nagios_log() {
	# Try to locate the nagios log, fallback to messages log
	for log in /var/log/nagios/nagios.log /var/log/nagios3/nagios.log /var/log/messages
	do
		if [ -e "${log}" ]; then
			echo ${log}
			return 0
		fi
	done
	return 3
}

LOG=$(find_nagios_log) || exit_unknown "Unable to locate logfile for parsing"

tail -n 1 ${LOG} &> ${TMP} || exit_unknown "Unable to parse logfile: $(cat ${TMP})"
tail -n 2000 ${LOG} | \
grep -E "$CURRENT_HOUR|$LAST_HOUR" | \
grep "Passive check result was received" | \
grep -i "could not be found"  | \
sed 's/.*Passive check result was received for service //' | \
sed 's/, but the host could not be found.*//' | \
sort | uniq > $TMP


LINES=`cat $TMP | wc -l`
PERFDATA="'ghost_services'=$LINES"
if [ $LINES -gt 0 ]; then
	echo "$LINES ghost services found in Nagios log files | $PERFDATA" 
	echo ""
	cat $TMP
	rm -f $TMP
	exit 1
fi

echo "No ghost services found in Nagios log files | $PERFDATA"
rm -f $TMP
exit 0