一个测试网卡流量的shell脚本

#!/bin/bash
#filename：monitor_interface.sh
function usage
{
   echo "use ./test_net.sh ethX time"
   echo "$1 is you network interface "
   echo "$2 is the last time!"
   echo "for example: ./test_net.sh eth0 2"
   exit 100
}

if [ $# -lt 2 -o $# -gt 2 ];then
  usage
fi

eth=$1
time=$2

old_inbw=`cat /proc/net/dev | grep $eth | awk -F'[: ]+' '{print $3}'`
old_outbw=`cat /proc/net/dev | grep $eth | awk -F'[: ]+' '{print $11}'`

while true
do
  sleep $time
  new_inbw=`cat /proc/net/dev | grep $eth | awk -F'[: ]+' '{print $3}'`
  new_outbw=`cat /proc/net/dev | grep $eth | awk -F'[: ]+' '{print $11}'`
  inbw=`expr $((($new_inbw-$old_inbw)/$time))`
  outbw=`expr $((($new_outbw-$old_outbw)/$time))`
  echo "$eth: IN:$inbw bytes  OUT:$outbw bytes"
  old_inbw=${new_inbw}
  old_outbw=${new_outbw}
done
exit 0

[root@jbxue shell]# ./test_net.sh  eth0 2
eth0: IN:3097 bytes  OUT:50374 bytes
eth0: IN:3158 bytes  OUT:44202 bytes
eth0: IN:2587 bytes  OUT:58932 bytes
eth0: IN:2104 bytes  OUT:51543 bytes