实用的shell脚本之（一）

一：查看网卡实时流量

#该脚本源自：博客园-吕振江
#文章地址为：https://www.cnblogs.com/lvzhenjiang/p/16251352.html

#!/bin/bash
while true
do

n=1
while (($n<=$(cat /proc/net/dev | wc -l)))
do    # 获取当前时刻网口接收与发送的流量
    Rb_pre[$n]=$(cat /proc/net/dev | grep : | sed -n "${n}p" | awk '{print $2}')
    Rp_pre[$n]=$(cat /proc/net/dev | grep : | sed -n "${n}p" | awk '{print $3}')
    Tb_pre[$n]=$(cat /proc/net/dev | grep : | sed -n "${n}p" | awk '{print $10}')
    Tp_pre[$n]=$(cat /proc/net/dev | grep : | sed -n "${n}p" | awk '{print $11}')
    inet[$n]=$(cat /proc/net/dev | grep : | sed -n "${n}p" | sed 's/:/ /g' | awk '{print $1}')
    ((n+=1))
done

sleep 1

m=1
while (($m<=$(cat /proc/net/dev | wc -l)))
do   # 获取1秒后网口接收与发送的流量
  Rb_next[$m]=$(cat /proc/net/dev | grep : | sed -n "${m}p" | awk '{print $2}')
    Rp_next[$m]=$(cat /proc/net/dev | grep : | sed -n "${m}p" | awk '{print $3}')
    Tb_next[$m]=$(cat /proc/net/dev | grep : | sed -n "${m}p" | awk '{print $10}')
    Tp_next[$m]=$(cat /proc/net/dev | grep : | sed -n "${m}p" | awk '{print $11}')
    ((m+=1))
done
clear

  echo -e "IP\t  RX-bytes\t   TX-bytes\t  RX-packets\t  TX-packets\t  TIME"

i=1
while (( $i<=`expr ${#Rb_pre[*]} - 2`))
do
  RXb[i]=$((Rb_next[i]-Rb_pre[i]))  #在$取值的时候，括号里面只需要跟变量即可（变量可自行进行计算）
  TXb[i]=$((Tb_next[i]-Tb_pre[i]))

  RXp[i]=$((Rp_next[i]-Rp_pre[i]))
  TXp[i]=$((Tp_next[i]-Tp_pre[i]))

ipadd[i]=$(ifconfig ${inet[i]} | grep "inet " | awk '{print $2}')    #获取网卡IP地址

  if [ ${RXb[i]} -lt 1024 ];then
    RXb[i]="${RXb[i]}B/s"
  elif [ ${RXb[i]} -gt 1048576 ];then
    RXb[i]=$(echo ${RXb[i]} | awk '{print $1/1048576 "MB/s"}')
  else
    RXb[i]=$(echo ${RXb[i]} | awk '{print $1/1024 "KB/s"}')
  fi
 # 判断接收流量如果大于MB数量级则显示MB单位,否则显示KB数量级
  if [ ${TXb[i]} -lt 1024 ];then
    TXb[i]="${TXb[i]}B/s"
  elif [ ${TXb[i]} -gt 1048576 ];then
    TXb[i]=$(echo ${TXb[i]} | awk '{print $1/1048576 "MB/s"}')
  else
    TXb[i]=$(echo ${TXb[i]} | awk '{print $1/1024 "KB/s"}')
  fi

  if [ ${RXp[i]} -lt 1000 ];then
   RXp[i]=${RXp[i]}
  else
   RXp[i]=$(echo ${RXp[i]} | awk '{print $1/1000 "K"}')
   fi

  if [ ${TXp[i]} -lt 1000 ];then
   TXp[i]=${TXp[i]}
  else
   TXp[i]=$(echo ${TXp[i]} | awk '{print $1/1000 "K"}')
  fi

  echo -e "${ipadd[i]} \t ${RXb[i]} \t  ${TXb[i]} \t  ${RXp[i]} \t  ${TXp[i]} \t  `date +%k:%M:%S` "

  let "i++"
done
done