- var_dump: documentation ( source)
- preg_match_all: documentation ( source)
<?php
$text = 'My Name is #P_NAME# and \r\n I am #P_AGE# years old';
$r = '#[^#]+#';
//$r = '#[(?<name>\S+)\]#';
//$r = '#.+?#';
//$r = '#(.+?)#';
//$r = '#\w*#';
preg_match_all('/'.$r.'/m', $text, $m);
var_dump($m);