有时候想看看网段中有哪些IP被用了，可以用这个快速ping做一个初步的判断。可以自己指定测试IP网段，并将测试结果整理排序到文件。

#!/bin/bash

#V1.0 2019-09-10

#Ping test shell script by tutor

clear

>ip-up.txt

>ip-down.txt

while true;

 do

    read -p "Please input the ip segment for ping test(like 192.168.100) : "  segment

     if [ -z $segment  ] ; then

       segment="192.168.100"

     fi

    echo -n "the ip segment is ${segment} , are you sure to continue [y/n] ? "

    read  action

     if [ -z $action  ] ; then

          break

     fi

     if [  "$action" =  "y"  ]; then

         break

     fi

done

echo "ping test is ready to run! "

for i in  {1..254}

 do

      {

        ping -c2 -W1 ${segment}.${i}  &>/dev/null

        if [ $? -eq 0 ]; then

           echo "${segment}.$i is up" &>/dev/null  >> ip-up.txt

        else

           echo "${segment}.$i is down" &>/dev/null >> ip-down.txt

        fi

     }&

done

wait

            sort -n -k 4 -t . ip-up.txt -o ip-up.txt

            cat ip-up.txt

            sort -n -k 4 -t . ip-down.txt -o ip-down.txt

            cat ip-down.txt

echo "ping test are finished!"