#! /bin/sh

case $# in
1) dataFile=$1; imageFile="";;
2) dataFile=$1; imageFile=$2;;
*) echo "syntax: dataFile imageFile" 1>&2; exit;;
esac

if [ "$imageFile" = "" ]
then 
gnuplot -persist <<EOF
set log xy
set xlabel "buffer size (bytes)"
set ylabel "time (sec)"
plot "$dataFile" with lines
EOF
else
gnuplot <<EOF
set terminal png
set log xy
set xlabel "buffer size (bytes)"
set ylabel "time (sec)"
set output "$imageFile"
plot "$dataFile" with lines
EOF
fi