#!/bin/bash

i=eth1
n=1

if [ "$1" != "" ]; then i="$1"; fi
if [ "$2" != "" ]; then n="$2"; fi

width=`stty size | cut -f 2 -d ' '`
max=`expr $width - 10`
startt=`date +%s`

a=`cat /sys/class/net/$i/statistics/rx_bytes`
b=$a
while sleep $n; do
	v=`expr $a - $b`
	if [ $v -gt $max ]; then
		max=$v
		echo -n ''
	fi
	printf '%8s ' $v
	echo -n ''
	seq -s = 0 `dc -e "$v $width 9 - * $max / p"` | sed 's/[^=]//g;'
	echo -n ''
	b=$a
	a=`cat /sys/class/net/$i/statistics/rx_bytes`
done