#!/bin/sh


init="$(($(cat /sys/class/net/[ew]*/statistics/rx_bytes | paste -sd '*')))"

printf "Recording bandwidth. Press enter to stop."

read -r

ending="$(($(cat /sys/class/net/[ew]*/statistics/rx_bytes | paste -sd '+')))"

printf "%4sB of bandwidth used. \\n" "$(numfmt --to=iec $((ending-init)))"