You're very welcome, ranceh!

I've been testing this for the last little bit and I think I found something else.

It wont match more than one entry per zone file. But there are more stanzas in each zone file.

When I googled this, I see that I should change the trailing end of a regex to /m for multiple matches, but when I do, I don't get any. What am I missing?

The m modifier will not help here. I (incorrectly) assumed that there was only one zone stanza per file. Processing multiple zone stanzas requires globally matching and preventing part of the regex from being 'greedy.' Try the following line:

$hash{$1} = $2
   while $data =~ /zone\s+"([^"]+)".+?masters\s+{[\s#\/]*([a-zA-Z0-9.-
+]+)[\s#\/;]*}/sg;
[download]

You'll note that: while has replaced if, there's a ? right after the + preceding masters, and the globally modifier is used.

while is used to process all matches; the ? prevents the regex from being 'greedy,' so it doesn't start the match at the beginning of a zone stanza and end the match with the last stanza.