关于shell:Linux实时流量监控

#!/bin/bash
#ens33为本机网卡名称
eth0=ens33
echo  -e    "流量进入--流量传出    "
while true; do
 old_in=$(cat /proc/net/dev |grep $eth0 |awk '{print $2}')
 old_out=$(cat /proc/net/dev |grep $eth0 |awk '{print $10}')
 sleep 1
 new_in=$(cat /proc/net/dev |grep $eth0 |awk '{print $2}')
 new_out=$(cat /proc/net/dev |grep $eth0 |awk '{print $10}')
 in=$(printf "%.1f%s" "$((($new_in-$old_in)/1024))" "KB/s")
 out=$(printf "%.1f%s" "$((($new_out-$old_out)/1024))" "KB/s")
 echo "$in $out"
done