if(/\s*Listen\s+(\S*)/){
       $instdetails{$instnum}{Listen}{$1}=1;
       $instdetails{$instnum}{Listen}{$1}{host}=gethost($1);
       next;
}

##</code><code>##

printf "\n%-20s","Listen:";
$hashref=$instdetails{$instnum}{Listen};
foreach $listen(keys %$hashref){
        $host=$instdetails{$instnum}{Listen}{$listen}{host};
        printf "\n%-20s$listen ($host)","";
}