iconv – allows file conversion between charsets – encodings – UTF-8 -t ISO-8859-1

iconv.man.txt – allows (file?) conversion between charsets / encodings

all available encodings: iconv_debian8_convertable_charsets.txt

example:

iconv -f UTF-8 -t ISO-8859-15 file.input -o file.output

file file.output
file.output ASCII text

iconv -f ASCII -t UTF-8 file.input -o file.output
file.output: ASCII text