Michael: Created page with "== Runlevel Control == While the run levels are generally defined, the specific services that are started up in each run level can be controlled. Each run level has a direco..."

2013-09-06T13:17:19Z

Created page with "== Runlevel Control == While the run levels are generally defined, the specific services that are started up in each run level can be controlled. Each run level has a direco..."

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== Runlevel Control ==

While the run levels are generally defined, the specific services that are started up in each run level can be controlled.

Each run level has a direcotry which defined the services to be started. As an example for run level 3, the directory /etc/rc3.d defines the services.

When the system is started a command is run which will locate the run levels directory. The loop defined in the /etc/rc.d/rc file will start each script in turn. The files are named K<number><service> and S<number><service>. The services are started in order starting with the K files and then the S files.

<syntaxhighlight>
exec /etc/rc.d/rc $RUNLEVEL
</syntaxhighlight>

== Stop a script booting for a run level ==

There are two ways to change which services are booted for a run level.

=== Manual changes ===

Rename the service file in /etc/rc.d/rc<runlevel> from S* or K* to something else.

=== Command Line Changes ===

Use the chkconfig command to check and change the run levels

<syntaxhighlight>
chkconfig --list postfix
postfix 0:off 1:off 2:on 3:on 4:on 5:on 6:off
</syntaxhighlight>

<syntaxhighlight>
chkconfig <service> on #turn a service on for run levels 2-5
chkconfig <service> off #turn a service off for run levels 2-5
chkconfig --level 4 <service> on #turn a service on for run level 4
</syntaxhighlight>

Redhat:Runlevel control - Revision history

Michael: Created page with "== Runlevel Control == While the run levels are generally defined, the specific services that are started up in each run level can be controlled. Each run level has a direco..."