An alternative to mail is a real-time conversation with another user. The talk command requests a conversational link to another user by specifying that user's logonid:
talk <logonid><hostname>
You will see a message "Waiting for your party to respond" as the talk daemon waits for the message recipient to enter the ''talk <yourlogonid><yourhostname>'' confirmation string. Once a connection is established, a horizontally split window is created which separates your editing space (the top section) from the recipient's editing space. What you type is displayed simultaneously on the top of your talk window, and on the bottom of the recipient's window. To end the conversation, indicate to the recipient that you are leaving, then enter the interrupt sequence <ctrl-c> to break the connection.