The bitwise OR (|) operator compares two numbers on a bit level and returns a number where the bits of that number are turned on if either of the corresponding bits of either number are 1. For example:

    a:  00101010  42
    b:  00001111  15       
================
a | b:  00101111  47

Note that the bitwise | operator can only create results that are greater than or equal to the larger of the two integer inputs.

So remember, for every given bit in a and b:

0 | 0 = 0
0 | 1 = 1 
1 | 0 = 1
1 | 1 = 1

Meaning

110 (6) | 1010 (10) = 1110 (14)