--start -1d gives a graph of the last day;
--start -1w gives a graph of the last week;
--start -1m gives a graph of the last month;
--start -1y gives a graph of the last year;

#! /bin/sh

cd /var/log/rrd
rrds=`find . -type f -name '*.rrd' | cut -c3-`

for i in $rrds;
  do
  j=`echo $i | sed 's/.rrd//'`
  rrdtool graph /var/www/rrd/$j-day.png --start -1d DEF:pkt=$i:packet:AVERAGE LINE1:pkt#ff0000:Packets/sec
  rrdtool graph /var/www/rrd/$j-week.png --start -1w DEF:pkt=$i:packet:AVERAGE LINE1:pkt#ff0000:Packets/sec
  rrdtool graph /var/www/rrd/$j-month.png --start -1m DEF:pkt=$i:packet:AVERAGE LINE1:pkt#ff0000:Packets/sec
  rrdtool graph /var/www/rrd/$j-year.png --start -1y DEF:pkt=$i:packet:AVERAGE LINE1:pkt#ff0000:Packets/sec
done
cd -
		

--start "yesterday"
--start "-1month"
--start "-2weeks"
--start "-1year"
--start -86400 (24*60*60=86400)
		

end

rrdtool graph graph.png --title="Test Graph" --start=0 --end=start+86400 --width=800 DEF:pkt=datafile.rrd:packets:AVERAGE \
  LINE1:pkt#ff0000:Packets