INIT.D(7) The SuSE boot concept INIT.D(7)NAME
INIT.D - The SuSE boot concept
SYNOPSIS
/etc/init.d/*
/etc/sysconfig
DESCRIPTION
The scripts for controlling the system are placed in /etc/init.d/ (they
have been moved according to the Linux Standard Base (LSB) specifica‐
tion). These scripts are executed directly or indirectly by
/sbin/init, the father of all processes. The configuration of
/sbin/init is given by the file /etc/inittab (see inittab(5)).
At boot time, the boot level master script /etc/init.d/boot is called
to initialise the system (e.g. file system check, ...). It also exe‐
cutes some hardware init scripts linked into /etc/init.d/boot.d/. Then
it calls /etc/init.d/boot.local, which executes the local commands.
After system startup, /sbin/init will normally switch on the default
run level given in /etc/inittab. It calls the run level master script
/etc/init.d/rc to start or stop services provided by the other scripts
under /etc/init.d/.
Both scripts, then boot level master script /etc/init.d/boot and the
the run level master script /etc/init.d/rc starts all other boot or
runlevel scripts either sequential or partial parallel within their
dependencies order.
To control the services of a run level, the corresponding scripts are
linked into run level directories /etc/init.d/rc<X>.d/, where
<X>=0,1,2,3,4,5,6,S is the run level number.
There are two kinds of symbolic link: start links, which are called
when entering a run level, and stop links, which are called when leav‐
ing a run level. Note that each service in the run levels 2, 3, 4, and
5 consists of a start and a stop link. Within SuSE boot concept a dif‐
ferential link scheme is used to be able to change a runlevel in com‐
parision with the former level.
If parallel executing of the boot scripts is enabled (see /etc/syscon‐
fig/boot variable RUN_PARALLEL) then both master scripts uses the pro‐
gram startpar(8) which starts or stops multiple services in parallel.
Startpar(8) will look for the files /etc/init.d/.depend.boot,
/etc/init.d/.depend.start, and /etc/init.d/.depend.stop to get the
dependencies for each service. The files will be written, beside the
symbolic links in the boot and runlevel directories, by the program
insserv(8).
To avoid redundant starts when changing run levels, only those services
are started which have no start link in the previous run level. And to
avoid redundant stops when changing run levels, only those services are
stopped which have no start link in the current level. To control this
behaviour, the names of the scripts are added on the names of the start
and stop links.
To control the order of service starts and stops, the start and stop
links include a number in their link name.
The system configuration files in /etc/sysconfig contain most of the
variables used to configure the installed services. These variables
can easily be changed by YaST or by using an editor. After using an
editor, the script /sbin/SuSEconfig must be called to distribute the
settings into the system.
Some details
The script /etc/init.d/lpd starts or stops the line printer daemon for
the printing service, according to the flag used:
/etc/init.d/lpd start
and
/etc/init.d/lpd stop
To do this automatically in run level 3, this script is linked into
/etc/init.d/rc3.d/ with these two symbolic links
/etc/init.d/rc3.d/S20lpd -> ../lpd
and
/etc/init.d/rc3.d/K20lpd -> ../lpd
The corresponding link with the letter S is used to start a service.
For the printing service the number between the letter S and the name
should be greater than the number of the start link of the network ser‐
vice. The corresponding link with the letter K is used to stop a ser‐
vice. The number of the stop link for the printing service should be
less than that of the stop link for the network service so that the
printer daemon is stopped before shutting down the network service.
Run levels and their services
0 This level is used for halting the system. The only valid ser‐
vice for this level is the script halt, which is linked into
/etc/init.d/rc0.d/. The script halt executes
/etc/init.d/halt.local. Special system issues for halt or
reboot should be added there.
6 This level is used for rebooting the system. The only valid ser‐
vice for this level is the script reboot, which is linked into
/etc/init.d/rc6.d/. The script reboot executes
/etc/init.d/halt.local. Specials system issues for halt or
reboot should be added there.
S This mode is used to switch from boot phase into single user
mode. The last valid service for this mode is the script sin‐
gle, which is linked into /etc/init.d/rcS.d/. In this mode you
have only one console.
1 According to the Linux Standard Base (LSB) specification this
runlevel is used to switch from normal runlevel into single user
mode. This is different from former SuSE Linux versions!
2 The run level 2 is without remote networking. Note that on some
other systems this is identical with the single user mode. This
run level can have more than one virtual console.
3 The run level 3 is with network. This run level is for server
stations not automatically running X.
5 The level 5 is with network and xdm(1). You should have a con‐
figured and perfectly running X Window System for this work sta‐
tion run level.
4 The run level 4 is not (yet) used.
/etc/init.d/skeleton
This script is a model for writing your own. You can use
insserv(8) to include your own script into a run level.
FILES
/etc/init.d/*
/etc/init.d/boot
/etc/init.d/boot.local
/etc/init.d/halt
/etc/init.d/halt.local
/etc/init.d/rc
/etc/init.d/reboot
/etc/init.d/skeleton
/etc/init.d/single
/etc/init.d/boot.d/S[0-9][0-9]*
/etc/init.d/rc0.d/{K,S}[0-9][0-9]*
/etc/init.d/rc1.d/{K,S}[0-9][0-9]*
/etc/init.d/rc2.d/{K,S}[0-9][0-9]*
/etc/init.d/rc3.d/{K,S}[0-9][0-9]*
/etc/init.d/rc4.d/{K,S}[0-9][0-9]*
/etc/init.d/rc5.d/{K,S}[0-9][0-9]*
/etc/init.d/rc6.d/{K,S}[0-9][0-9]*
/etc/init.d/rcS.d/{K,S}[0-9][0-9]*
/etc/init.d/.depend.boot
/etc/init.d/.depend.start
/etc/init.d/.depend.stop
/etc/inittab
/etc/sysconfig/boot
/etc/sysconfig
SEE ALSOinsserv(8), startpar(8), init(8), inittab(5), and the SuSE Linux hand‐
book, chapter The SuSE boot concept.
COPYRIGHT
1996-2005 SuSE Linux AG, Nuernberg, Germany.
AUTHORS
Florian La Roche <http://www.suse.de/feedback>, Werner Fink <wer‐
ner@suse.de>, Burchard Steinbild <http://www.suse.de/feedback>.
4.4 Berkeley Distribution Nov 15, 2000 INIT.D(7)
