$re = '/type=dog[\s\S]*?name=(\w+)[\s\S]*?(color=(\w+))?/m';
$str = 'type=dog
sex=male
name=wolf
color=brown
type=dog
sex=male
name=bob
type=cat
sex=male
name=tom
color=black
type=dog
sex=female
name=simona
color=white';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($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