I have tested \\v (vertical white space) for matching \\r\\n and their combinations, but I found out that \\v does not match \\r
To match every LINE of a given String, simple use the ^$ Anchors and advice your regex engine to operate in multi-line mode. Then ^$ will match the start and end of each line, instead of the whole strings start and end.
http://php.net/manual/en/reference.pcre.pattern.modifiers.php
in PHP, that would be the m modifier after the pattern. /^(.*?)$/m will simple match each line, seperated by any vertical space inside the given string.
Btw: For line-Splitting, you could also use split() and the PHP_EOL constant:
$lines = explode(PHP_EOL, $string);