usage: /usr/bin/preconv [-dr] [-D fallback-encoding] [-e encoding] [file ...]
usage: /usr/bin/preconv {-v | --version}
usage: /usr/bin/preconv {-h | --help}

Read each file, convert its encoded characters to a form GNU troff(1)
can interpret, and send the result to the standard output stream.
The default fallback encoding is 'latin1'.  See the preconv(1) manual page.