Eina per buscar rangs de IPs lliures

Et busca 6 ips consequtives. Se li passa de paràmetre un rang:

./ipsearch.sh  172.25.33

#!/bin/bash
base=$1
let count=0
for i in `seq 1 256`
do
 ip=`curl --silent
http://guifi.net/es/guifi/menu/ip/ipsearch/$base.$i | grep 172 | grep
device`
 echo $ip
 if [ "$ip" != "" ]
 then
   count=0
 fi
 let count=$count+1
 if [ $count -eq 8 ]
 then
   let i=$i-7
   echo $base.$i
   exit 1
 fi
done