實時輸出linux網卡流量資訊

#!/bin/bash                                                                                        
 
# -------------------------------------------------------------------------------                  
# Filename:    netflood.sh                                                                         
# Revision:    1.2                                                                                 
# Date:        2007/08/30                                                                          
# Author:      Ajian                                                                               
# Email:       ajian521#gmail.com                                                                  
# Website:     www.ohlinux.com                                                                     
# Description: LAN traffic monitor                                                                 
# -------------------------------------------------------------------------------                  
# Copyright:   2009 (c) Ajian                                                                      
# License:     GPL                                                                                 
#                                                                                                  
# This program is free software; you can redistribute it and/or                                    
# modify it under the terms of the GNU General Public License                                      
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty
# of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# -------------------------------------------------------------------------------
#Version 1.1 2007/08/30
#create the script
#Version 1.2 2008/01/10
#modify the script and add the variable.
NIC=eth1
while : ; do
        time=`date +%m"-"%d" "%k":"%M`
        day=`date +%m"-"%d`
        rx_before=`ifconfig $NIC|sed -n "8"p|awk '{print $2}'|cut -c7-`
        tx_before=`ifconfig $NIC|sed -n "8"p|awk '{print $6}'|cut -c7-`
        sleep 2
        rx_after=`ifconfig $NIC|sed -n "8"p|awk '{print $2}'|cut -c7-`
        tx_after=`ifconfig $NIC|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