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.

If you have the password, try logging on as root now. Enter the whoami
command to verify your identity. Then log out immediately. When you're
root, the kernel will not protect you from yourself, because root has
permission to do anything at all to the system. Don't experiment while
you're root. In fact, don't do anything as root unless absolutely
necessary. This isn't a matter of security, but rather of stability. Your
system will run much better if it can keep you from making mistakes.

You may find the su command more convenient than logging in as root. su
allows you to assume the identity of another user, usually root unless you
specify someone else. (You can remember that su stands for Super User,
though some say it stands for Set UserID.)

Here's something to try. Log on as yourself - that is, not as root. Then
your session will look something like the one in Figure 4.1.

When you're doing system administration tasks, you should do as much as
possible as yourself. Then use su, do the part that requires root
privileges, and use the exit command to turn off privileges so you can no
longer harm anything.