Using a look-ahead combined with pos avoids any need for sums and finds overlapping matches (if that is part of your spec.).

$ perl -Mstrict -Mwarnings -E '
my $str = qq{\0} x 32;
substr $str,  5,  2, qq{\x0b\x9e};
substr $str, 26,  5, qq{\x3c\x5a\x1e\x6b\x48};
substr $str, 11, 11, qq{\x0f\x2c\x34\x3c\x5a\x1e\x6b\x48\x0b\x9e\x88};
say unpack q{H*}, $str;

for my $quant ( 8, 4, 2 )
{
    say q{};
    say qq{$quant [\\x0a-\\x9f] found at @{ [ pos $str ] }}
       while $str =~ m{(?x) (?= [\x0a-\x9f] {$quant} ) }g;
}'
00000000000b9e000000000f2c343c5a1e6b480b9e88000000003c5a1e6b4800

8 [\x0a-\x9f] found at 11
8 [\x0a-\x9f] found at 12
8 [\x0a-\x9f] found at 13
8 [\x0a-\x9f] found at 14

4 [\x0a-\x9f] found at 11
4 [\x0a-\x9f] found at 12
4 [\x0a-\x9f] found at 13
4 [\x0a-\x9f] found at 14
4 [\x0a-\x9f] found at 15
4 [\x0a-\x9f] found at 16
4 [\x0a-\x9f] found at 17
4 [\x0a-\x9f] found at 18
4 [\x0a-\x9f] found at 26
4 [\x0a-\x9f] found at 27

2 [\x0a-\x9f] found at 5
2 [\x0a-\x9f] found at 11
2 [\x0a-\x9f] found at 12
2 [\x0a-\x9f] found at 13
2 [\x0a-\x9f] found at 14
2 [\x0a-\x9f] found at 15
2 [\x0a-\x9f] found at 16
2 [\x0a-\x9f] found at 17
2 [\x0a-\x9f] found at 18
2 [\x0a-\x9f] found at 19
2 [\x0a-\x9f] found at 20
2 [\x0a-\x9f] found at 26
2 [\x0a-\x9f] found at 27
2 [\x0a-\x9f] found at 28
2 [\x0a-\x9f] found at 29
$

[download]

I hope this is helpful.

Cheers,

JohnGG

In reply to Re: matching characters and numbers with regex by johngg
in thread matching characters and numbers with regex by james28909

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