What’s the difference between
PATH_INFO variable is only present if you invoke a PHP script like this:
It's only the
/HELLO_THERE part after the
.php script. If you don't invoke the URL like that, there won't be a
$_SERVER["PATH_INFO"] environment variable.
PORIG_ prefix is somewhat uncommon.
PATH_INFO is a standard CGI-environment variable, and should never be prefixed. Where did you read that? (There were some issues around PHP3/PHP4 if you invoked the PHP interpreter via cgi-bin/ - but hardly anyone has such setups today.)
For reference: http://www.ietf.org/rfc/rfc3875