check something with hexdump
echo -e "ä" | iconv -f UTF-8-MAC -t UTF-8 |hexdump echo -e "ä\c" | iconv -f UTF-8-MAC -t UTF-8 |hexdump echo -e "ä\c" | iconv -f UTF-8-MAC -t UTF-8 |hexdump -C printf '\xc3\xa4' |hexdump