网络流量监控shell脚本

网络收发包计数记录在 /proc/net/dev 文件中, 要取得流量, 只需要读取里面的内容两次, 然后相减, 再除以时间间隔即可.

#!/bin/bash

#Usage1,record in file:    netmonitor <MinKB> <Interval> <FileName>
#Usage2,print on terminal: netmonitor <MinKB> <Interval>
#Record the value great than 100KB, 3 second Interval:
#Example1,record: netmonitor 100 3 xxx.txt
#Example2,print: netmonitor 100 3

#参数说明
#第一个是速度记录的下限，单位是KB，即超过多少KB才记录，0为全部记录
#第二个参数是采样间隔，即隔多少秒记录一次
#第三个参数是输出的文件名，为空的话就直接在终端打印

#xieqianli
#2011-4-25

#同时修改下列变量可以固定参数，使用脚本时就无需参数
MinKB="$1"
Interval="$2"
FileName="$3"
NetDev="wlan0"

#检查参数完整性
if [ "$Interval" == "" ];then
    echo "Usage1,record in file:     netmonitor <MinKB> <Interval> <FileName>"
    echo "Usage2,print on terminal:  netmonitor <MinKB> <Interval>"
    echo "Record the values great than 100KB, 3 seconds Interval:"
    echo "Example1,record:   netmonitor 100 3 xxx.txt"
    echo "Example2,print:    netmonitor 100 3"
    exit 1
fi

#检查 MinKB 参数的合法性
check=`echo $MinKB | grep "[^0-9]"`
if [ "$check" != "" ];then
    echo "$MinKB is not a number"
    exit 0
fi

len=${#MinKB}
char1=`echo $MinKB | cut -c 1`
if [ $(($len)) -gt $((1)) -a "$char1"=="0" ];then
    echo "$MinKB is not a number"
    exit 0
fi

#检查 Interval 参数的合法性
check=`echo $Interval | grep "[^0-9]"`
if [ "$check" != "" ];then
    echo "$Interval is not a number"
    exit 0
fi

len=${#Interval}
char1=`echo $Interval | cut -c 1`
if [ $(($len)) -gt $((1)) -a "$char1"=="0" ];then
    echo "$Interval is not a number"
    exit 0
fi

while [ 1 ]
do
    #读取已接收和已发送字节数，间隔一秒
    REC1=`cat /proc/net/dev | grep $NetDev | sed 's/:/ /' | tr -s " " | cut -d " " -f 3`
    SEND1=`cat /proc/net/dev | grep $NetDev | sed 's/:/ /' | tr -s " " | cut -d " " -f 11`
    sleep $Interval
    REC2=`cat /proc/net/dev | grep $NetDev | sed 's/:/ /' | tr -s " " | cut -d " " -f 3`
    SEND2=`cat /proc/net/dev | grep $NetDev | sed 's/:/ /' | tr -s " " | cut -d " " -f 11`

    if [ $((REC2)) -lt $((REC1)) ];then
        exit 1
    fi

    if [ $((SEND2)) -lt $((SEND1)) ];then
        exit 1
    fi

    RESULT_REC=$((($REC2-$REC1)/$Interval))
    RESULT_SENT=$((($SEND2-$SEND1)/$Interval))

    #进行B,KB和MB的单位换算
    if [ $RESULT_REC -lt $((1024)) ]; then
        SPEED_REC="$RESULT_REC B "
    elif [ $RESULT_REC -gt $((1024)) -a $RESULT_REC -lt $((1048576)) ]; then
        SPEED_REC="$(($RESULT_REC/1024)) KB"
    elif [ $RESULT_REC -gt $((1048576)) ];then
        SPEED_REC="$(($RESULT_REC/1048576)) MB"
    fi

    if [ $RESULT_SENT -lt $((1024)) ]; then
        SPEED_SENT="$RESULT_SENT B "
    elif [ $RESULT_SENT -gt $((1024)) -a $RESULT_SENT -lt $((1048576)) ]; then
        SPEED_SENT="$(($RESULT_SENT/1024)) KB"
    elif [ $RESULT_SENT -gt $((1048576)) ];then
        SPEED_SENT="$(($RESULT_SENT/1048576)) MB"
    fi

    #求时间
    TIME=`date`

    #左边填充空格，把结果进行右对齐
    ZERO=$((8-${#SPEED_REC}))
    for (( i=0; i<$ZERO; i=i+1 ))
    do
        SPEED_REC=" $SPEED_REC"
    done

    ZERO=$((8-${#SPEED_SENT}))
    for (( i=0; i<$ZERO; i=i+1 ))
    do
        SPEED_SENT=" $SPEED_SENT"
    done

    REC_KB="$(($RESULT_REC/1024))"
    SEND_KB="$(($RESULT_SENT/1024))"

    #过滤掉小于 MinKB 的记录
    if [ "$MinKB" != "0" -a $((REC_KB)) -lt $MinKB -a $((SEND_KB)) -lt $MinKB ];then
        continue
    fi

    #输出结果
    if [ "$FileName" = "" ];then
        echo "$TIME    Receive:$SPEED_REC    Send:$SPEED_SENT"
    else
        echo "$TIME    Receive:$SPEED_REC    Send:$SPEED_SENT" >> $FileName
    fi
done