utf8::encode( $s ) if utf8::is_utf8( $s );

did you mean "encode() unless is_utf8()"?

file operators suffer from The Unicode Bug
What does this mean in this context? I wasn't able to trigger incorrect filenames with any ARGV; but the following did, and seems to be what you're referring to: 
IO::File->new( chr (0xbb), q(>))

[download]
So what should I do -- always encode args to open()?

As for Windows, is there a "best practices" prelude somewhere? I've seen a lot of confusing answers, and I wasn't even attempting to tackle it, but now that you've mentioned it I'd like to know.

In reply to Re^2: how are ARGV and filename strings represented? by almr
in thread how are ARGV and filename strings represented? by almr

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