$re = '/^#monfiltreperso3$.+?^#FIN$[\r\n]*/sm';
$str = '#MESSAGE
:0
* ^(To|cc).*fd.*
|/usr/bin/vacation fd
#monfiltreperso
:0
* ^From.*martial@gironde.comFIN
Maildir/.repertorymoi
#FIN
#monfiltreperso2
:0
* ^Subject:.*monsujet2
Maildir/.repertorymoi2
#FIN
#monfiltreperso3
:0
* ^From.*martial2@gironde.com
Maildir/.repertorymoi2
#FIN';
preg_match($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