# UDP errors 2.0
# Francesco Latini
# www.francescolatini.net

function log {
	date=`date +%H:%M:%S`
        err=`netstat -su | grep errors | awk '{print $1}'`

        # calcolo il delta
	if [ "$1" -eq "0" ]; then 
		delta="-"
	else
        	last=`tail -1 ${log} | awk '{print $2}'`
        	delta=`echo "${err}-${last}" | bc`
	fi
	
        # loggo il delta
        echo -e "${date}\t${err}\t${delta}" >> ${log}
}

if [ -z "$1" ]; then 
	echo "Usage: ./udp_errors.sh [opzione] secondi"
	exit
fi

log=/var/tmp/udp_errors.log
limit=$1

# controllo se esiste gia` un file di log
if [ -f "$log" ]; then 
	echo -e "\n=== `date` ===\n" >> ${log}
	log 0
else
	touch ${log} && echo -e "=== `date` ===\n*Creato il file di log\n" >> ${log}
	log 0
fi

sleep $limit

# comincio a contare gli UDP errors
for ((c=1; c<=limit; c++)); do
	log 1
        sleep $limit
done