in reply to logical-assignment operators
As others have said, the first pair are conditions and the second pair are bitwise operations, and you can learn all about them in perlop. For a little more illustration, I'll show Perl that does the same thing without the operators you're asking about.
Conditions:
if ( ! $v ) { $v = $w } # $v ||= $w; if ( $x ) { $x = $y } # $x &&= $y;
Bitwise operations:
$v = $v | $w; # $v |= $w $x = $x & $y; # $x &= $y
|
|---|