my $addr;

while (! $addr){
    print "enter a damned FQDN: ";
    my $input = <STDIN>;
    chomp $input;

    $addr = inet_aton($input);
}

my $ip = inet_ntoa($addr);

##</code><code>##

my $addr = inet_aton($input);

die "invalid hostname specified\n" if ! $addr;

my $ip = inet_ntoa($addr);

...