Best way to convert text files between character sets?

Question

What is the fastest, easiest tool or method to convert text files between character sets?

Specifically, I need to convert from UTF-8 to ISO-8859-15 and vice versa.

Answer 1

DOS/Windows: use Code page

chcp 65001>NUL
type ascii.txt > unicode.txt

Command chcp can be used to change the code page. Code page 65001 is Microsoft name for UTF-8. After setting code page, the output generated by following commands will be of code page set.