$re = '/use ((?:([a-z_0-9]*)\.)*)(\w*);/im';
$str = '-------------------------------------------------------------------------------
library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;
use work.pk_avalon_mm_extif_defs.all;
use work.common_tb_pkg.all;
package common_register_interface_pkg is';
preg_match($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