You can also move around on the command line to make changes. The easiest way is with the Left and Right Arrow keys. Try typing whoasmi instead of whoami, and then use the Left Arrow key to move back to the s. You can erase the s with the Backspace or Delete keys.
There are more advanced features as well (no need to memorize them all now, though). Try pressing Ctrl-a. This moves you to the beginning of the line. Ctrl-k (the k stands for “kill”) deletes all characters until the end of the line; try it from the middle of the command line. Using Ctrl-a followed by Ctrl-k, you can delete the entire command line. Ctrl-y pastes the last thing you killed, reinserting it at the current cursor position (y stands for “yank,” as in “yank it back”). Ctrl-e will move the cursor to the end of the command line.
Go ahead and play around with command-line editing to get a feel for it. Experiment.
Because Debian is a multiuser system, it’s designed to keep any one user or program from breaking the entire system. The kernel will not allow normal users to change important system files. This means that things stay the way they’re supposed to, safe from accidents, viruses, and even malicious pranks. Unlike other operating systems, Debian is safe from these threats. You won’t need an anti-virus program.
However, sometimes you need to change important system files; for example, you might want to install new software or configure your network connection. To do so, you have to have greater powers than a normal user; you must become the _root user_ (also called the _superuser_).
To become root, just log on with the username root and the root password; this was set during installation, as described in section 3.15 on page [*].
At many sites, only the system administrator has the root password, and only the system administrator can do the things that one must be root to do. If you’re using your own personal computer, _you_ are the system administrator, of course. If you don’t have root privileges, you will have to rely on your system administrator to perform any tasks that require root privileges.
Sometimes you’ll have the root password even on a shared corporate or educational server, because the system administrator trusts you to use it properly. In that case, you’ll be able to help administer the system and customize it for your needs. But you should be sure to use the password responsibly, respecting other users at all times.