A trick for the global matching that I have had occasion to use in the past.

I was trying to parse a fixed delimited report. But the locations of the columns was not fixed. However there was a header, something like this:

Here     Be Many    Columns
-------- ---------- ---------
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To locate the positioning of the columns I found the line with the underlines and then:

my @space_loc;
while ($line =~ / /g) {
  push @space_loc, pos($line);
}
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You can also put together a small "parse engine" as a demo of \G matching. Handling the CSV spec might be a good example.