#!/bin/bash  

while [ "1" ]  

do  

eth=$1  

RXpre=$(cat /proc/net/dev | grep $eth | tr : " " | awk '{print $2}')  

TXpre=$(cat /proc/net/dev | grep $eth | tr : " " | awk '{print $10}')  

sleep 1  

RXnext=$(cat /proc/net/dev | grep $eth | tr : " " | awk '{print $2}')  

TXnext=$(cat /proc/net/dev | grep $eth | tr : " " | awk '{print $10}')  

clear  

echo  -e  "t RX `date +%k:%M:%S` TX"  

RX=$((${RXnext}-${RXpre}))  

TX=$((${TXnext}-${TXpre}))  

if [[ $RX -lt 1024 ]];then  

RX="${RX}B/s"

elif [[ $RX -gt 1048576 ]];then  

RX=$(echo $RX | awk '{print $1/1048576 "MB/s"}')  

else  

RX=$(echo $RX | awk '{print $1/1024 "KB/s"}')  

fi  

if [[ $TX -lt 1024 ]];then  

TX="${TX}B/s"

elif [[ $TX -gt 1048576 ]];then  

TX=$(echo $TX | awk '{print $1/1048576 "MB/s"}')  

else  

TX=$(echo $TX | awk '{print $1/1024 "KB/s"}')  

fi  

echo -e "$eth t $RX   $TX "  

done