#!/usr/bin/perl
use strict;

my $inputText = "word1, word2, #18abcdefgh ,word4";

print "before: $inputText\n";

if ($inputText =~ s/#(\d)(\d{\1})(.{\2})/\<Binary block: $2 bytes\>/)
	{
	print "(1) = $1\n";
	print "(2) = $2\n";
	print "(3) = $3\n";
	}

print "after: $inputText\n";