bandwith2

#!/bin/bash
BR1=`cat /sys/class/net/eth0/statistics/rx_bytes`
BT1=`cat /sys/class/net/eth0/statistics/tx_bytes`
sleep 30
BR2=`cat /sys/class/net/eth0/statistics/rx_bytes`
BT2=`cat /sys/class/net/eth0/statistics/tx_bytes`
INKB=$(((($BR2-$BR1) /30) /1024))
OUTKB=$(((($BT2-$BT1) /30) /1024))
echo `expr $INKB / 30` "IN"
echo `expr $OUTKB / 30` "OUT"