You have new mail in /var/spool/mail/root

Every so often while I’m in SSH, I would get an alert:

You have new mail in /var/spool/mail/root

It’s just an alert, but it gets annoying seeing it appear after every single command. After searching around the web, I found a very simple way to get rid of it, using the following command.

> /var/spool/mail/root