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From: Leif M. <le...@ta...> - 2003-10-09 13:21:02
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Arun,
What are run levels? Well that is a subject that I could spend all
night explaining, and
has nothing to do with the Wrapper directly.
Basicly, the UNIX system operates in various runlevels when it is in
different states.
For example, when the system normally boots up, it goes into what is
called "multi user mode",
or run level #2. Then when the system is shutting down, it goes into
"halt", level #0, or
"reboot", level #6 runtime level. If you are having problems with your
system, you may wish
to boot into a "single user" mode. This is called run level #1.
If you look in the rc*.* directories, you will see a list of shell
scripts that are executed
when ever the system enters a specific run level. The scripts within
each directory are
executed in the order specified by their names.
"Snn_xxx" means that the "xxx" script will be executed with an
order of "nn", and be
passed the "start" parameter.
"Knn_xxx" means that the "xxx" script will be executed with an order
of "nn" and be
passed the "stop" parameter.
All of the scripts in run level #2, /etc/rc2.d/, will be executed on
startup. And then
all scripts in /etc/rc0.d/ will be executed on shutdown.
So if you placed a symbolic link to your wrapper script in the
following 2 directories:
/etc/rc0.d/K20myapp
/etc/rc2.d/S20myapp
Then your "myapp" application would be called with "myapp start" on
system startup and
then "myapp stop" on system shudown.
Make sense?
Here is one site which kind of explains it. I remember the first
time I tried to figure
run levels out. There are not many sites out there which explain it in
an easy to
understand way.
http://www.pucmmsti.edu.do/materias/fnunez/RUTE_TUT/node35.html
Please consider donating to the project if you have found this
information useful.
Answering questions to make it possible for you to do your job takes
real time.
Donations put me in a great mood and make me look forward to hearing
from you
again.
http://wrapper.tanukisoftware.org/doc/english/donate.html
Cheers,
Leif
Ramachandra, Arun wrote:
> The help docs for starting the wrapperlistener app at reboot says:
> "We will want our application to be started for all multi-user run
> levels and stopped for the halt, single-user and reboot runlevels."
>
> I did not quite understand what this means.
> Could anybody please explain? What exactly is meant by a run level?
>
> -Thanks
> -Arun
>
>
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