To send a message to someone whose username is ezekiel, simply enter the command
mail ezekielYou will be prompted for the Subject: of your message. The subject field gives the purpose of the message, and is used to construct a table of contents for a mailbox. It should be short.
After you type the subject and hit return, you may begin typing your message. The possibilities for editing are meager here. Keep the lines short. If you make a mistake, you may edit the line in the same manner as when you enter a command (backspace, Ctrl-u, etc). After you hit Enter you are more-or-less committed. (Actually, there are ways to edit the line after you hit Enter, but using emacs to edit and send your message is much preferable. See below.) If you want to start over completely, hit Ctrl-c twice. Finally, when you are finished typing your message, and are ready to send it, hit Ctrl-d to signal an end-of-file.
The mailer will then prompt with Cc:. You may send a copy of the message to another user, or even to yourself by entering the appropriate address. If you chose not to, simply hit Enter
You may send mail to more than one user by giving a list, with items separated by commas: