The first argument of map is code executed for every other argument of map. 

print map uc($_),    qw( a b c d );  # Prints ABCD
print map { uc($_) } qw( a b c d );  # Same thing

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unpack '(A4)*', $val splits the value into as many 4 byte blocks as possible. I would have used "W" instead of "A", though. unpack '(W4)*', $val splits the value into as many 4 character blocks as possible.

@_ is not unamed —its name is @_— and nothing is being stored in it —its contents are being passed to map.

@_ holds the arguments of the current function (convert).

In reply to Re^3: Corrupt Data? by ikegami
in thread Corrupt Data? by spickles

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