new_contents: #coding:utf-8
  #-------------
  #Author:Hu
  #Data:20150520
  #-------------
  
  from __future__ import division
  import re
  import time
  from optparse import OptionParser
  
  
  def getbandwidth(eth='eth0',intevel=1):
      a=open('/proc/net/dev')
      data=a.read()
      patten=eth + '.*'
      if  not re.search(patten,data):
          print "The ETHname not have"
          exit(1)
      Rev_old=re.search(patten,data).group().replace(':',' ').split()[1]
      Send_old=re.search(patten,data).group().replace(':',' ').split()[9]
      a.close()
  
      while True:
          #print intevel
          time.sleep(int(intevel))
          a=open('/proc/net/dev')
          data=a.read()
          Rev=re.search(patten,data).group().replace(':',' ').split()[1]
          Send=re.search(patten,data).group().replace(':',' ').split()[9]
          diff_Rev=int(Rev)-int(Rev_old)
          diff_Sen=int(Send)-int(Send_old)
          diff_M=diff_Rev*8/1024/1024/int(intevel)
          diff_S=diff_Sen*8/1024/1024/int(intevel)
          print time.strftime("%Y%m%d %H:%M:%S") + '   The Recevie is  %6.2f Mbps(byte is %d)' % (diff_M,diff_Rev) + '   The Send is  %6.2f Mbps(byte is %d)' % (diff_S,diff_Sen)
          Rev_old=Rev
          Send_old=Send
          a.close()
  if __name__=='__main__':
      
      import sys
      usage='''%prog [-i ethname] [-t interveltime]
             Example:%prog -i eth0 -t 1'''
      parser=OptionParser(usage=usage,version='2.0_20150602')
  
      parser.add_option('-i','--interface',dest='interface',default='eth0',help='Wann to interface')
      parser.add_option('-t','--time',dest='intevel',type='int',default='1',help='The intevel time')
      (options,args)=parser.parse_args()
      print "The interafce is %s and the intevel time is %d" % (options.interface,options.intevel)
      getbandwidth(options.interface,options.intevel)
  
subject: add linux bandwidth tool