open FO, ">test.txt";
binmode FO, ":utf8";
print FO "\u00b9"

##</code><code>##

print FO "\u-00b9";  # Outputs -00b9
print FO "\u{00b9}"; # Outputs {00b9}
print FO "\x{00b9}"; # Outputs a strange character (the code for 00b9 is a superscript 1}