#!/bin/sh start="$(($(cat /sys/class/net/$1/statistics/rx_bytes | paste -sd '+')))" end="$(($(cat /sys/class/net/$1/statistics/rx_bytes | paste -sd '+')))" if [ "$2" ]; then delay="$2" else delay=10 fi printf "Recording bandwidth.\n" report() { printf '%4dB\n' $(numfmt --to=iec $(($end - $start))) } trap report SIGINT while sleep "$delay"; do report done