Mailx is a Unix console application mail program. It has two major modes: send mode and receive mode. In send mode users can send messages using standard input. The receive mode is more interactive and allows users to read incoming mail and to send mail. Mailx has a number of available options that you can activate using a simple text-editor syntax. To send a message to multiple recipients there are a few steps you must follow.
Begin the mail command using the following syntax: mailx [-s "subject"]. The portion in brackets allows you to enter a subject line for your message. Type your actual subject in the quotation marks in lieu of the word subject.
Enter the email address of your first recipient after the brackets. The command should now read: mailx [-s "subject"] firstname.lastname@example.org
Enter the email address or addresses of any other recipients you wish to receive the message separated by a space. For example: mailx [-s "subject"] email@example.com firstname.lastname@example.org email@example.com
Key in the body or text of the message after the address line and press "CTRL" and "D" to send it.