#!/bin/sh dev="$1" start="$(($(cat /sys/class/net/$dev/statistics/rx_bytes | paste -sd '+')))" end="$start" if [ "$2" ]; then delay="$2" else delay=10 fi printf "Recording bandwidth.\n" report() { end="$(($(cat /sys/class/net/$dev/statistics/rx_bytes | paste -sd '+')))" numfmt --to=iec $(($end - $start)) } trap report SIGINT while sleep "$delay"; do report done