Almost every user and many administrators never see what happens while the system boots, and those who do often do not understand what they are seeing. Those who do often are not sure what is happening. From the time you flip the power switch to the time you get that first login: prompt, dozens of things must happen, many of which happen long before the system knows that it's running Linux. Knowing what is happening as the system boots and in what order it is happening is very useful when your system does not start the way it should.
In this chapter, I will first talk about starting your system. Although you can get it going by flipping on the power switch and letting the system boot by itself, there are many ways to change the behavior of your system as it boots. How the system boots depends on the situation. As we move along through the chapter, we'll talk about the different ways to influence how the system boots.
After we talk about how to start your system, we'll look at a few ways to alter your system's behavior when it shuts down.