What does "or" in php mean? [duplicate]

Question

Possible Duplicate:
PHP - and / or keywords

I saw several bits of PHP code using or in a way I was unfamiliar with. For example:

fopen($site,"r") or die("Unable to connect to $site");

Is this equal to this ||?

Why would you use this instead of a try catch block? What will cause the program run the or die()?

Answer 1

It is for the most part, but...

The reason for the two different variations of "and" and "or" operators is that they operate at different precedences.

See http://php.net/manual/en/language.operators.logical.php

Answer 2

or is equal to || except that || has a higher presedense than or.

Reference:

http://www.php.net/manual/en/language.operators.precedence.php