After you’ve logged into the Pi or after you’ve started a new terminal from the desktop, you’ll see the following prompt awaiting your commands:
pi@raspberrypi ~ $
It doesn’t look like much, but it already gives you a lot of information. For example, the first part (pi@raspberrypi) tells you that the host name of your computer is raspberrypi. It also tells you that your username is pi. This is an important piece of information, because Linux is a multiuser operating system. This means that multiple people can work on the same computer simultaneously (over a network, for example). Also, you can switch to another user account whenever you need to, so it’s good to know who you are at the moment.
The next part of the prompt ...