>perl -le"binmode STDOUT, ':encoding(iso-latin-1)'; print qq{print length '\x85'}" | perl -l
1   Good

>perl -le"binmode STDOUT, ':utf8'; print qq{print length '\x85'}" | perl -l
2   BAD!

>perl -le"binmode STDOUT, ':utf8'; print qq{use utf8; print length '\x85'}" | perl -l
1   Good