use strict;
my $str = 'Lorem ipsum dolor sit amet, consectetur adipiscing elit. Sed condimentum velit a felis commodo, ac efficitur nunc [size=27]Hello World[/size] dictum. Fusce auctor, [size=30]This is a test[/size] sit amet hendrerit commodo, [size=59]The quick brown fox jumps over the lazy dog[/size] enim augue consectetur nulla, vel blandit magna est vel sapien. Nam [size=42]Lorem ipsum dolor sit amet[/size] mattis ligula eu [size=41]Happiness is a warm puppy[/size] condimentum rhoncus. [size=21]Short[/size] Interdum et malesuada fames ac ante ipsum primis in faucibus. Donec interdum, [size=50]Supercalifragilisticexpialidocious[/size] ut posuere sapien venenatis vel.';
my $regex = qr~(?*.{24,40}(.*))
(?=\[size=\d+].*?\[/size]\1$)
.{0,39}t.*?(?=\1$)~mxp;
if ( $str =~ /$regex/g ) {
print "Whole match is ${^MATCH} and its start/end positions can be obtained via \$-[0] and \$+[0]\n";
# print "Capture Group 1 is $1 and its start/end positions can be obtained via \$-[1] and \$+[1]\n";
# print "Capture Group 2 is $2 ... and so on\n";
}
# ${^POSTMATCH} and ${^PREMATCH} are also available with the use of '/p'
# Named capture groups can be called via $+{name}
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Perl, please visit: http://perldoc.perl.org/perlre.html