#!/bin/sh if [ -z "$1" ]; then echo "usage: $0 file [center]" 1>&2 exit 1 fi if [ ! -f "$1" ]; then echo "$1: not found" 1>&2 exit 1 fi c=${2:--25} gnuplot -persist <<EOF set xlabel "MHz" set ylabel "dB" set yrange [$c-5:$c+5] set grid plot "<sed '\$d' $1" using (\$1):(log(\$3)/log(10)*10) with lines notitle EOF