查看网卡流量

查看网卡流量除了用iftop等工具外，我们也可以自己写个脚本，它的优势就是在服务器比较卡的时候查看资源不会占用很多系统资源！

#!/bin/bash
NAME=nic_flow
PIDFILE=/var/tmp/$NAME.pid
LOGFILE=/var/tmp/$NAME.log

function start(){
    if [ -f "$PIDFILE" ]; then
        echo $PIDFILE
        exit 2
    fi
    for (( ; ; ));do
        eth=$1
        [ -z "${eth:-}" ] && eth=eth0
        time_range=$2
        [ -z "${time_range:-}" ] && time_range=1
        ifconfig  | awk '{print $1}' | grep "eth" > /dev/null
        [ $? -gt 0 ] && echo "wrong NIC device" && exit 10
        RX_1=$(cat /proc/net/dev | grep "$eth" | awk -F'[ |:]+'  '{print $4}')
        TX_1=$(cat /proc/net/dev | grep "$eth" | awk '{print $9}')
        sleep $time_range
        RX_2=$(cat /proc/net/dev | grep "$eth" | awk -F'[ |:]+'  '{print $4}')
        TX_2=$(cat /proc/net/dev | grep "$eth" | awk '{print $9}')
        clear
        echo  -e "`date +%k:%M:%S`      RX        TX" | tee -a $LOGFILE
        RX=$((${RX_2}-${RX_1}))
        TX=$((${TX_2}-${TX_1}))
        if [[ $RX -lt 1024 ]];then
            RX="${RX}B/s"
        elif [[ $RX -gt 1048576 ]];then
            RX=$(echo $RX | awk '{print $1/1048576 "MB/s"}')
        else
            RX=$(echo $RX | awk '{print $1/1024 "KB/s"}')
        fi
        if [[ $TX -lt 1024 ]];then
            TX="${TX}B/s"

        elif [[ $TX -gt 1048576 ]];then
            TX=$(echo $TX | awk '{print $1/1048576 "MB/s"}')
        else
            TX=$(echo $TX | awk '{print $1/1024 "KB/s"}')
        fi
        echo -e " $eth       $RX        $TX " | tee -a $LOGFILE
    done&
    echo $! > $PIDFILE
}
function stop(){
    [ -f $PIDFILE ] && kill `cat $PIDFILE` && rm -rf $PIDFILE
}

case "$1" in
  start)
    start $2 $3
    ;;
  stop)
    stop
    ;;
  *)
    echo $"Usage:$0  {start|stop,NIC device(eth*), time_range(s)}"
    exit 2
esac

使用

[root@localhost ~]# ./nic_flow.sh start
3:38:44      RX        TX
eth0       3B/s        138B/s
[root@localhost ~]# ./nic_flow.sh stop

这个脚本可以接受额外的两个参数：网卡参数和时间间隔参数！

[root@localhost ~]# ./nic_flow.sh start lo 5
 5:50:05      RX        TX
 lo       2B/s        0B/s
[root@localhost tmp]# tail  /var/tmp/nic_flow.log
 5:47:04      RX        TX
 eth0       1B/s        0B/s
 5:47:05      RX        TX
 eth0       1B/s        0B/s
 5:49:55      RX        TX
 lo       0B/s        0B/s
 5:50:00      RX        TX
 lo       0B/s        0B/s
 5:50:05      RX        TX
 lo       2B/s        0B/s