It all depends on which UNIX shell you are currently running. Here you can type various commands in. For example, type ls for a directory listing, cat to view the contents of a file, or pine to check your email. Note that UNIX is case sensitive . So PINE and Pine are not the same as typing pine .
Lets check e-mail by typing pine , then hitting the enter key .
You won't use the mouse in a telnet session. You will have to use the keyboard. After you execute the pine application, you'll see a menu interface . You can use the arrow keys to navigate, up and down, to the different options. You can also simply type the appropriate letter.