Hi,
Marking this old bug as done.
Having 'dd' operate on multibyte characters would be strange since
characters may span across block boundries and case conversion may
change the length of characters in Unicode.
POSIX discussed this in 2011 and determined that 'dd' should only
operate on unibyte locales. No one made an issue on their tracker
though, so it never made it into the actual text. I created an issue
recently and a future release should say the following [1]:
If a character to be mapped or a character resulting from the
mapping is not a single-byte character, the behavior is unspecified.
I documented this in the manual with a commit today [2].
Thanks,
Collin
[1] https://austingroupbugs.net/view.php?id=1959
[2]
https://github.com/coreutils/coreutils/commit/3b809382b8dca9a13f5afe46d4f6569db06fad10
