$ piconv -f ISO-8859-1 -t utf8 -s '©'
©

$ piconv -t ISO-8859-1 -f utf8 -s '©'
©

##</code><code>##

$ piconv -f ISO-8859-1 -t utf8 \
>     -s '<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">'
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">

$ piconv -f ISO-8859-1 -t utf8 \
>     -s '<meta name="registered sign" content="®">'
<meta name="registered sign" content="®">