$re = '/(?<=\/)(\/[^\/]+\/|[^\/\n]+)(?:\/|$)/m';
$str = '/string1/string2/string3//regexp1///regexp2///regexp3//string4//regexp4/
/string1/string2/string3//regexp1///regexp2///regexp3//string4//regexp4//
/string1/string2/string3//regexp1///regexp2///regexp3//string4/
/string1/string2/string3//regexp1///regexp2///regexp3//string4//regexp4/';
preg_match_all($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