Linux boots

Linux boots

Runlevels At any given time on a Linux system, a certain base set of processes is running.
This state of the machine is called its runlevel, and it is denoted with a number
from 0 through 6. The system spends most of its time in a single runlevel.
However, when you shut the machine down, init switches to a different runlevel
in order to terminate the system services in an orderly fashion and to tell the k




The easiest way to get a handle on runlevels is to examine the init
configuration file, /etc/inittab. Look for a line like the following:


id:5:initdefault:

This line means that the default runlevel on the system is 5. All lines in the
inittab file take this form, with four fields separated by colons occurring
in the following order: # A unique identifier (a short string, such as id in
the preceding example) # The applicable runlevel number(s) # The action that
init should take (in the preceding example, the action is to set the
default runlevel to 5) # A command to execute (optional)