linux下自动检测eth0网卡带宽的脚本

#!/bin/bash
#network
while : ; do
      time=`date "+%Y-%m-%d %H:%M:%S"`
      rx_before=`ifconfig eth0|sed -n "8"p|awk '{print $2}'|cut -c7-`
      tx_before=`ifconfig eth0|sed -n "8"p|awk '{print $6}'|cut -c7-`
      sleep 2
      rx_after=`ifconfig eth0|sed -n "8"p|awk '{print $2}'|cut -c7-`
      tx_after=`ifconfig eth0|sed -n "8"p|awk '{print $6}'|cut -c7-`
      rx_result=$[(rx_after-rx_before)/256]
      tx_result=$[(tx_after-tx_before)/256]
      echo "$time Now_In_Speed: "$rx_result"kbps Now_OUt_Speed: "$tx_result"kbps"
      sleep 2
done