Off-label uses of pandoc: conversion between text encodings.
E.g., UTF-8 to UTF-16:
echo 'X' | pandoc lua -e 'io.write(pandoc.text.toencoding(io.read"a", "utf-16"))'
Other direction:
echo 'X' | pandoc lua -e 'io.write(pandoc.text.fromencoding(io.read"a", "utf-16"))'
The set of supported encodings is platform dependent, but always includes UTF-8, UTF-16, UTF-32, and latin1.