Datasheet

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page 279). After doing so, check whether the system works in the desired

way by entering init 5. If everything turns out as expected, you can use

YaST to set the default runlevel to 5.

Caution

Modifying /etc/inittab

If /etc/inittab is damaged, the system might not boot

properly. Therefore, be extremely careful while editing

/etc/inittab and always keep a backup of an intact ver-

sion. To repair damage, try entering init=/bin/sh after the

kernel name at the boot prompt to boot directly into a shell. After

that, replace /etc/inittab with your backup version using cp.

Caution

11.3 Changing Runlevels

Generally, two things happen when you change runlevels. First, stop

scripts of the current runlevel are launched, closing down some programs

essential for the current runlevel. Then start scripts of the new runlevel are

started. Here, in most cases, a number of programs are started. For exam-

ple, the following occurs when changing from runlevel 3 to 5:

1. The administrator (root) tells init to change to a different runlevel by

entering init 5.

2. init consults its conﬁguration ﬁle (/etc/inittab) and determines it

should start /etc/init.d/rc with the new runlevel as a parameter.

3. Now rc calls all the stop scripts of the current runlevel, but only for

those where there is no start script in the new runlevel. In this exam-

ple, these are all the scripts that reside in /etc/init.d/rc3.d/

(old runlevel was 3) and start with a K. The number following K spec-

iﬁes the order to start, as there are some dependencies to consider.

4. The last things to start are the start scripts of the new runlevel. These

are, in this example, in /etc/init.d/rc5.d/ and begin with an S.

The same procedure regarding the order in which they are started is

applied here.

When changing into the same runlevel as the current runlevel, init only

checks /etc/inittab for changes and starts the appropriate steps (e.g.,

for starting a getty on another interface).

268 11.3. Changing Runlevels