$re = '~(?:/\*|\G(?!^))(?:(?!\*/)[^$])*\K\$var\s*=\s*(?:(?!\*/)[^$;])*~';
$str = '/* other code $var = value1 */
$var = value2 ;
/*
other code
$var = value3 ;
other code
*/
$var = value4;
$var = value5;
/*
other code
$var = value6;
$var = value7;
$var = value8
*/';
preg_match_all($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