sar

sar –n DEV查看网络流量

sar –n DEV 1 2

$  cat  monitor_net.sh
############################################################
#!/bin/bash

ethn=$1

while true
do
  RX_pre=$(cat /proc/net/dev | grep $ethn | sed 's/:/ /g' | awk '{print $2}')
  TX_pre=$(cat /proc/net/dev | grep $ethn | sed 's/:/ /g' | awk '{print $10}')
  sleep 1
  RX_next=$(cat /proc/net/dev | grep $ethn | sed 's/:/ /g' | awk '{print $2}')
  TX_next=$(cat /proc/net/dev | grep $ethn | sed 's/:/ /g' | awk '{print $10}')

  clear
  echo -e "\t RX `date +%k:%M:%S` TX"

  RX=$((${RX_next}-${RX_pre}))
  TX=$((${TX_next}-${TX_pre}))

  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 "$ethn \t $RX   $TX "

done
############################################################

https://www.jianshu.com/p/3332296056f2