#!/bin/sh
olddata=`/sbin/ifconfig wlan0|awk -F: '/TX bytes/ {print $3}'|cut -f1 -d' '`
while true; do
  sleep 1
  data=`/sbin/ifconfig wlan0|awk -F: '/TX bytes/ {print $3}'|cut -f1 -d' '`
  echo `expr \( $data - $olddata \) / 128` Kib/s
  olddata=$data
done