#!/bin/ksh

IP1=10
IP2=20
IP3=30
IP4=40

set -A a
n=1
for i in $IP1 $IP2 $IP3 $IP4
do
        if [ $i ]; then
                a[$n]=$i
                ((n=n+1))
        fi
done

for i in ${a[*]}
do
        echo $i
done