(solved)what's means about "PINB |= 1<<5"

Using Arduino Programming Questions
10

To make it more interesting, here is what the same compiler did to a slightly different code:

 PINB |= (1<<7) | (1<<6);
    00009A   B103             IN      R16,PINB
    00009C   6C00             ORI     R16,0xC0
    00009E   B903             OUT     PINB,R16
 PINB  = (1<<7) | (1<<6);
    0000A0   EC00             LDI     R16,0xC0
    0000A2   B903             OUT     PINB,R16

Stuff like this would be a nightmare to debug. That's probably something like this is rarely seen - the authors of the arduino reference made the right call.

For the record, I always use PORTx ^= (1<<7); for something like this.