#!/bin/awk -f

BEGIN {
	while ("for f in /sys/class/net/[ew]*; do paste $f/statistics/[rt]x_bytes; done" | getline) {
		d+=$1; u+=$2; }
	getline < "/tmp/test"; od=$1; ou=$2; ot=$3;
	getline < "/proc/uptime"; t=$1;
	print d,u,t > "/tmp/test";
	t=t-ot; if (!t) t=1;
	printf "%.1f/%.1f MB/s\n", ((d-od)/1000000)/t, ((u-ou)/1000000)/t;
}