Mail handling and receiving
The mail program enables you to examine each message in a mailbox and then delete or file a message in a personal mail directory.
The command shell notifies you that mail has arrived. The notification
is displayed before the next prompt, provided that the MAIL environment
variable is set and provided that the interval specified by MAILCHECK has
elapsed since the shell last checked for mail. The notification message is
the value of the MAILMSG environment
variable. Depending on which shell you are using (bourne, korn, or C shell),
the notification is similar to the following:
YOU HAVE NEW MAIL