What is the use of a single | in PHP? [duplicate]

Possible Duplicate:

What is the difference between the | and || operators?

Reference - What does this symbol mean in PHP?

I am starting to use PHP again and I always remember using single |'s a lot and all my books are in storage, so I cant use them for a refrence and google doesnt give me very much. Any help appreciated!

bitwise OR http://www.php.net/manual/en/language.operators.bitwise.php

Bitwise Inclusive OR ( 5 = 0101) = ( 0 = 0000) | ( 5 = 0101) ( 5 = 0101) = ( 1 = 0001) | ( 5 = 0101) ( 7 = 0111) = ( 2 = 0010) | ( 5 = 0101) ( 5 = 0101) = ( 4 = 0100) | ( 5 = 0101) (13 = 1101) = ( 8 = 1000) | ( 5 = 0101)