$re = '/(((DC|MB)\d{2}[-]\d{2}[-]\d{2})|(CN0\d{1})|(SYSA)|(ppag)|(METR))/';
$str = 'DC00-01-14 blabla blabla MB00-07-10 blublu CN03 bli BLI2454 bli bli CN02 bloblo bloblo bloblo SYSA bloublou bloublou bloublou CN06 blaiblai fgdf+-*blaiblai blaiblai METR bly
bly blybly blybly ppag blublib/12-+kjflouBFD 454';
preg_match_all($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