>>>>> On Sun, 15 Nov 2015, Ulrich Mueller wrote:
> Description:
> In an UTF-8 locale like en_US.UTF-8, the case-modifying
> parameter expansions sometimes return invalid UTF-8 encodings.
> This seems to happen when the UTF-8 byte sequences that are
> encoding upper and lower case have different lengths.
Even more interesting effects happen if the string contains a
character whose UTF-8 encoding gets *longer* after case conversion,
because then the terminating null byte will be overwritten.
For example, U+0250 "LATIN SMALL LETTER TURNED A" is represented by a
two byte sequence in UTF-8, while its uppercase equivalent U+2C6F
needs three bytes:
$ LC_ALL=en_US.UTF-8
$ x=$'aaaaa\xc9\x90'
$ y=${x^^}
$ echo -n "$y" | od -t x1
0000000 41 41 41 41 41 e2 90 af 6f 6d 65 2f 75 6c 6d
0000017
y contains some trailing garbage (could be a part of $HOME or $PWD).
