
	-a	Turn on message acknowledgement.
	-b	Prompt for a "Bcc:" list (if not preset).
	-c	Prompt for a "Cc:" list (if not preset).
	-d	Incorporate "dead.letter".
	-e	Add a "Received:" line to the header.
	-f	Read and send letter from `stdin'.
	-i	Add a "Message-ID:" line to the header.
	-m	Ignore `.' commands on stdin.
	-o	Addresses invalid unless '@' present.
	-p	Print header on startup.
	-q	Report unique message ID on stdout.
	-r	No message return on remote error.
	-s	Don't prompt for a "Subject:" line.
	-t	Don't echo "To:" and "EOT" to `stdout'.
