The mail program offers a clumsy way of reading mail. If you type mail without any parameter, you'll see the following:
I'm going to send myself some mail so I can play around with the mailreader:
The prompt inside the mail program is an ampersand (``&''). It
allows a couple of simple commands, and will give a short help screen
if you type ? and then 
.
The basic commands for mail are:
What's a message-list? It consists of a list of integers seperated by spaces, or even a range, such as 2-4 (which is identical to ``2 3 4''). You can also enter the username of the sender, so the command t sam would type all the mail from Sam. If a message list is omitted, it is assumed to be the last message displayed (or typed).
There are several problems with the mail program's reading facilities. First of all, if a message is longer than your screen, the mail program doesn't stop! You'll have to save it and use more on it later. Second of all, it doesn't have a very good interface for old mail--if you wanted to save mail and read it later.
Emacs also has a facility for reading mail, called rmail, but it is not covered in this book. Additionally, most Linux systems have several other mailreaders available, such as elm; or pine;.