? to figure out commands to use.
But there are better ways to read the mail. As noted earlier,
mailx is an improved version. Even more user-friendly are mutt, cone and (al)pine. All of these are packaged by Debian and can be installed by apt-get
I find the mail program difficult to use. The mail is stored in a flat file, so I use
vi /var/spool/mail/user and manage it there.
mailx is present by default on most systems. Type
mailx to invoke it. Read the manpages to understand how to navigate the mailx interface.
You need some sort of mail client to be configured. I use alpine as it has basic text-GUI
and I used it somewhere previously and I am customed to it. Very easy to use, configurable, etc. btw. One way to manage is fetchmail:ing to some other location, if system has mail server installed. Plain .forward file with your mail address in it /home/dir is an option too! Don’t create a loop, though!