Are you asking how to get a total of all the results printed by printf "found %d zeros\n", $included_length =~ tr[0][];?

Update: I'll go with that assumption, and that you're looking for an elegant solution, by some subjective definition of elegant. A word of warning; elegance may be in the eye of the beholder. Anyway, here's my stab at it:

use strict;
use warnings;
no  warnings   'once';

use feature    'say';
use List::Util 'reduce';


my $cgs = '10001011101010010101101000010101101011101111010100101010101
+0';


sub substr_at { substr $_[0], $_[1], $_[2]-$_[1]; }


sub count_zeros {
  ( my $string, local $_ ) = @_;
  substr_at( $string, ( split )[1,2,1] ) =~ tr[0][];
}


say reduce { $a += count_zeros($cgs,$b) } 0, <DATA>;


__DATA__
junk 5  15
junk 23 59
junk 18 34
junk 10 20
junk 9  19
junk 40 49
[download]

Here's how it works:

• The reduce statement is self-documenting if you're familiar with List::Util::reduce; Iterating over the lines in the DATA filehandle, $b is passed each time to a subroutine that will count the zeros in a string. That value is then added to the $a(ccumulator). At the end, the final value of the accumlator, $a is returned as our sum.
• substr_at should also be self-documenting by its name; we specify the string, and then the "at" values (start at, end at). I'll grant that it would be clearer if I unpacked @_, but it's pretty simple to look at.
• count_zeros takes a target string, and a criteria string, and binds the substr_at of the string to the tr/// operator to return a count.

And the reason I think it's elegant is that it is uncluttered, and seems to flow nicely. At any level, from the low end (substr_at) to the high end (reduce), you can look at what's happening and understand without spending too much time trying to grok the code.

Keep in mind though, any time you're summing anything, there's a loop involved, whether you see it or not. In the code I provided, "reduce" loops over the contents of <DATA>. Internally there are other loops as well, such as the one that the transliteration operator must use to count matches in a string. But even though we know the loops are there, it's nice to work at a level of abstraction where we're not boringly typing out "foreach..."

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