If you are logged into RCS through a non-graphical remote connection, you cannot display a mailbox icon. Instead, it is possible for you to have a message displayed notifying that you have mail every time the UNIX prompt is displayed.
To do this, use an editor to place the following lines in your .bashrc file, replacing userid with your own userid:
MAILCHECK=900
MAILPATH=´/usr/spool/mail/userid´
MAILMSG=´You have mail´
Make sure there are no spaces surrounding the equals sign (=) and that the first word on each line is in all capital letters. This tells BASH, the program that prompts you for commands, to check for mail every time it prints a UNIX prompt, but no more frequently than every 15 minutes (900 seconds). If it finds mail, it prints the message You have mail.