Perl 5.8+ has UNICODE support integrated so that eq, regular expressions, etc all work without issue.

However, you need to decode the encoded bytes into UNICODE text strings. There are a few ways of doing that:

• Specify the encoding when you open the file from which the text originates.

  open(my $fh, '<:encoding(UTF-8)')
     or die;
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• Specify the encoding for the handle after it's already open.

  binmode(STDIN, ':encoding(UTF-8)');
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• Decode the encoded data manually.

  use Encode qw( decode );
  my $line_bytes = <$fh>;
  my $line_chars = decode('UTF-8', $line_bytes);
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Don't forget that you need to do the inverse — encode the characters into UTF-8 bytes — when you output.

If your source code is UTF-8 encoded, add use utf8; at the top of your file.

Of course, you'll need to find a way to deal with precomposed and combined characters. The easiest thing to do is to ignore it completely...

It won't handle the actual comparisons for you, but when dealing with (possibly) utf8 strings, Devel::StringInfo is your friend.