$re = '/^(?:dns|salt|rsys|arb|asplog|mri|ipt|sample|stat|setting|gid)\.e5\.sk$/mi';
$str = 'dns.e5.sk
salt.e5.sk
rsys.e5.sk
arb.e5.sk
asplog.e5.sk
mri.e5.sk
ipt.e5.sk
sample.e5.sk
stat.e5.sk
setting.e5.sk
gid.e5.sk';
preg_match_all($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