转：LINUX下查看网卡流量的脚本（完美修改版）

转载自 mnsch

最终编辑 wangpeng168

修改内容：

• 修复了会显示负数的问题
• 增加了bits/s的统计情况
• 增加了最后的汇总平均值

#!/bin/bash
# osdba 2008.10.22 monitor the interface's network traffic.
#   Zeuslion 2009.08.29.
if [ $# -ne 3 ];then
   echo Useage : $0 interface interval count
   echo Example: $0 eth0 2 10
   exit
fi
eth=$1
count=$3
interval=$2
inbytesfirst=$(cat /proc/net/dev |tr ':' ' '|awk '/'$eth'/{print $2}')
if [ -z "$inbytesfirst" ];then
    echo The network interface $eth is not exits!
    exit 1;
fi
outbytesfirst=$(cat /proc/net/dev |tr ':' ' '|awk '/'$eth'/{print $10}')
inpacketsfirst=$(cat /proc/net/dev |tr ':' ' '|awk '/'$eth'/{print $3}')
outpacketsfirst=$(cat /proc/net/dev |tr ':' ' '|awk '/'$eth'/{print $11}')
sleep $interval"s"
i=0
while [ "$i" -lt "$count" ]
do
   inbytesend=$(cat /proc/net/dev |tr ':' ' '|awk '/'$eth'/{print $2}')
   outbytesend=$(cat /proc/net/dev |tr ':' ' '|awk '/'$eth'/{print $10}')
   inpacketsend=$(cat /proc/net/dev |tr ':' ' '|awk '/'$eth'/{print $3}')
   outpacketsend=$(cat /proc/net/dev |tr ':' ' '|awk '/'$eth'/{print $11}')

   bytesin=$(($inbytesend-$inbytesfirst))
   bytesout=$(($outbytesend-$outbytesfirst))
   packetsin=$(($inpacketsend-$inpacketsfirst))
   packetsout=$(($outpacketsend-$outpacketsfirst))

   if [ "$bytesin" -lt "0" ];then
      bytesin=$((4294967295-$inbytesfirst+$inbytesend))
      #echo bytesin $bytesin $inbytesfirst $inbytesend
   fi
   if [ "$bytesout" -lt "0" ];then
      bytesout=$((4294967295-$outbytesfirst+$outbytesend))
      #echo bytesout $bytesout $outbytesfirst $outbytesend
   fi
   if [ "$packetsin" -lt "0" ];then
      packetsin=$((4294967295-$inpacketsfirst+$inpacketsend))
      #echo packetsin $packetsin $inpacketsfirst $inpacketsend
   fi
   if [ "$packetsout" -lt "0" ];then
      packetsout=$((4294967295-$outpacketsfirst+$outpacketsend))
      #echo packetsout $packetsout $outpacketsfirst $outpacketsend
   fi

   bytesin=$(($bytesin/$interval))
   bytesout=$(($bytesout/$interval))
   packetsin=$(($packetsin/$interval))
   packetsout=$(($packetsout/$interval))

   sumbytesin=$(($sumbytesin+$bytesin))
   sumbytesout=$(($sumbytesout+$bytesout))
   sumpacketsin=$(($sumpacketsin+$packetsin))
   sumpacketsout=$(($sumpacketsout+$packetsout))

   if [ $(($i%20)) -eq 0 ];then
      echo " ifname   | in_kbits/s out_kbits/s | in_kBytes/s out_kBytes/s | in_packets/s out_packets/s"
      echo "--------- | ---------- ----------- | ----------- ------------ | ------------ -------------"
   fi
   echo $eth $bytesin $bytesout $packetsin $packetsout |awk '{printf("%9s | %10d %11d | %11d %12d | %12d %13d\n",$1,$2/128,$3/128,$2/1024,$3/1024,$4,$5)}'
   inbytesfirst=$inbytesend
   outbytesfirst=$outbytesend
   inpacketsfirst=$inpacketsend
   outpacketsfirst=$outpacketsend
  
   i=$(($i+1))
   sleep $interval"s"
done

sumbytesin=$(($sumbytesin/$i))
sumbytesout=$(($sumbytesout/$i))
sumpacketsin=$(($sumpacketsin/$i))
sumpacketsout=$(($sumpacketsout/$i))

echo "--------- | ---------- ----------- | ----------- ------------ | ------------ -------------"
echo Average $sumbytesin $sumbytesout $sumpacketsin $sumpacketsout |awk '{printf("%9s | %10d %11d | %11d %12d | %12d %13d\n",$1,$2/128,$3/128,$2/1024,$3/1024,$4,$5)}'

输出示例：

[root@localhost nat]# ./ifstat.sh eth1 2 5
ifname   | in_kbits/s out_kbits/s | in_kBytes/s out_kBytes/s | in_packets/s out_packets/s
--------- | ---------- ----------- | ----------- ------------ | ------------ -------------
     eth1 |     204743      112824 |       25592        14103 |        38459         38172
     eth1 |     212353      111547 |       26544        13943 |        39025         38152
     eth1 |     204263      114007 |       25532        14250 |        38802         38233
     eth1 |     208357      111877 |       26044        13984 |        38706         38123
     eth1 |     215614      113400 |       26951        14175 |        39950         39375
--------- | ---------- ----------- | ----------- ------------ | ------------ -------------
Average |     209066      112731 |       26133        14091 |        38988         38411