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;

[download]

Bitwise operations: 

$v = $v | $w;              # $v |= $w
$x = $x & $y;              # $x &= $y

[download]

In reply to Re: logical-assignment operators by kyle
in thread logical-assignment operators by apomatix

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