sub nice_string {
join("",
        map { $_ > 255 ? # if wide character...
        sprintf("\\x{%04X}", $_) :  # \x{...}
        chr($_) =~ /[[:cntrl:]]/ ?  # if control character
        sprintf("\\x%02X", $_) :    # \x..
	chr($_)                     # else as themselves
	} unpack("U*", $_[0]));     # unpack Unicode
}