Universal Office Converter (unoconv) is a command line tool to convert any
document format that LibreOffice can import to any document format that
LibreOffice can export. It makes use of the LibreOffice's UNO bindings for
non-interactive conversion of documents.

For practical reasons we mention LibreOffice, but OpenOffice is supported by
unoconv as well.

WWW: http://dag.wieers.com/home-made/unoconv/