$re = '/.*((de)|(dk)|(no)|(jp))_2015.+/';
$str = '2
viatormobileprd_2015-12-05.tar.gz
3
viatorpartnerprd_2015-12-05.tar.gz
viatormpartnerprd_2015-12-05.tar.gz
viatorcomse_2015-12-05.tar.gz
viatormse_2015-12-05.tar.gz
4
viatorcomfr_2015-12-05.tar.gz
viatormfr_2015-12-05.tar.gz
viatorcomit_2015-12-05.tar.gz
viatormit_2015-12-05.tar.gz
viatorcomnl_2015-12-05.tar.gz
viatormnl_2015-12-05.tar.gz
5
viatorcomes_2015-12-05.tar.gz
viatormes_2015-12-05.tar.gz
viatorcombr_2015-12-05.tar.gz
viatormbr_2015-12-05.tar.gz
6
viatorcomde_2015-12-05.tar.gz
viatormde_2015-12-05.tar.gz
viatorcomdk_2015-12-05.tar.gz
viatorcomno_2015-12-05.tar.gz
viatorcomjp_2015-12-05.tar.gz
viatormjp_2015-12-05.tar.gz
';
preg_match_all($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