aaa111bbb
ab01ac  d ab02ac ab03ac
aaa222bbb  
ab04acab05ac r ab06ac
aaa333bbb  
ab01ac t cab06acab10ac 

##</code><code>##

111  
01,02,03
222  
04,05,06
333 
01,06,10

##</code><code>##

 use strict;
 use warnings;
 my $start = 'aaa';
 my $end   = 'bbb';
 my $start1 = 'ab';
 my $end1   = 'ac';
 my @matches = $content =~ /${start}([0-9]{3})${end}.*?${start1}([0-9]{2})${end1}/smg;