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