metamail

metamail [options] [filename]

Normally invisible to users, metamail is used to send and display rich text or multimedia email using MIME typing metadata. Mail-reading programs normally call metamail to determine how to handle the data, but metamail can be called directly by developers who want to use it for their own mail software, or by system administrators and power users adding lines to their printcap files. Any argument passed to metamail that is not preceded by a hyphen (-) is assumed to be the name of a file to read. If no filename is specified, standard input is assumed.