linux网络速率监控

#!/bin/bash
#作者：fafu_li
#时间：2015.10.14
#监控网卡传输速率

source /etc/profile            #加载系统环境变量
source $HOME/.bash_profile    #加载用户环境变量
set -o nounset                 #引用未初始化变量时终止执行,也可以set -u
#set -o errexit                #执行任何语句返回非0状态时终止执行,也可以set -e

#定义监控的网卡
INET=("eth0" "lo")

net_monitor() {
    interface=$1
    ifconfig $interface > /dev/null 2>&1
    if [[ $? != 0 ]];then
        echo "$interface 不存在"
    else 
        RX1=$(cat /proc/net/dev | grep $interface | awk -F ":" '{print $2}' | awk -F " " '{print $1}')
        TX1=$(cat /proc/net/dev | grep $interface | awk -F ":" '{print $2}' | awk -F " " '{print $9}')
        sleep 1
        RX2=$(cat /proc/net/dev | grep $interface | awk -F ":" '{print $2}' | awk -F " " '{print $1}')
        TX2=$(cat /proc/net/dev | grep $interface | awk -F ":" '{print $2}' | awk -F " " '{print $9}')
        let total_RX=$RX2-$RX1
        let total_TX=$TX2-$TX1
        if [ $total_RX -lt 1024 ];then
            total_RX="${total_RX} B/s"
        elif [ $total_RX -gt 1048576 ];then    
            total_RX=$(echo $total_RX | awk '{printf "%.2f",$1/1048576}')" MB/s"
        else
            total_RX=$(echo $total_RX | awk '{printf "%.2f",$1/1024}')" KB/S"
        fi
        if [ $total_TX -lt 1024 ];then
            total_TX="${total_TX} B/s"
        elif [ $total_TX -gt 1048576 ];then    
            total_TX=$(echo $total_TX | awk '{printf "%.2f",$1/1048576}')" MB/s"
        else
            total_TX=$(echo $total_TX | awk '{printf "%.2f", $1/1024}')" KB/S"
        fi
        echo "$interface 接收: $total_RX 发送: $total_TX"
    fi
}

while true;do
    echo "---------------------------------------------------------------"
    for i in ${INET[@]};do
        net_monitor $i
    done
done