$re = '/(\w+):\s+(.*)\r?\n/m';
$str = '/*
title: Introduction
*/
Introduction
============
[This is a link](http://google.com)
![This is an image](http://google.com/test.jpg)
* This is a list
* This is a list
* [This is a link](http://google.com)
* ![This is an image](http://google.com/test.jpg)';
preg_match($re, $str, $matches, PREG_OFFSET_CAPTURE, 0);
// Print the entire match result
var_dump($matches);
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 PHP, please visit: http://php.net/manual/en/ref.pcre.php