my $newfile = undef;
finddepth(
    sub {
        if (-M $_ <= 30){
            $newfile=$File::Find::name;
            goto done_finddepth;
        }
    },
    $base
);
done_finddepth:
die "the new file is $newfile";

##</code><code>##

    my $count = 0;
    &find(
      sub {
         $count++;
        File::Find::breakout() if $count == 500;
    }, '/');