#\u and \U in $'…' give a unicode character by its code
cRuble=$'\u20BD' #₽
cLambda=$'\u03BB' #λ
#${#var} counts characters, wc -c counts the bytes of UTF-8
rubleChars=${#cRuble}
#rubleChars is 1
rubleBytes=$(printf '%s' "$cRuble" | wc -c)
#rubleBytes is 3
#the code of a character: a quote before it, as for ASCII
printf -v lambdaCode 'U+%04X' "'$cLambda"
#lambdaCode is "U+03BB"
echo "cRuble is $cRuble"
echo "cLambda is $cLambda"
echo "rubleChars is $rubleChars"
echo "rubleBytes is $rubleBytes"
echo "lambdaCode is $lambdaCode"