Yatta !!!

!/bin/bash

function nextIP {
for i in {"1","2","3","4"};do
eval digit$i=$(echo $1| cut -d'.' -f$i)
done

            for i in {"4","3","2","1"};do
                    if [ $(eval echo "\${digit$i}") -lt 255 ];
                    then
                            let digit$i=$(eval echo "\${digit$i}")+1
                            IP="$digit1.$digit2.$digit3.$digit4"
                            return 0
                    else
                            let digit$i=0
                    fi
            done
            return 1
       }

nextIP $1
echo $IP