[Techtalk] Re: check if script parent process is "init"

[Rudi]

Hi,

Wolfgang Petzold <petzold at villa-chaos.de> writes:

> The init process usually runs scripts in /etc/init.d/ (or a similar
> location) by calling symlinks in "runlevel directories", /etc/rc?.d/
> in my (debian) case.

Hmm, of course, why didn't I think of it?
This would be then:

if echo $0 | grep -q "/etc.*/?rc.\.d/"
then
   echo thanks for calling me, init!
fi

> On the other hand, if I remember correctly what I once read about the
> boot process, the init process always has PID 1. So, if another (bash)
> process is started by init, bash should set its variable ${PPID} to 1
> accordingly.

That's true. And I must say, I like this idea better as a starting point
because it's distro-independent, whereas the exact rc?.d locations are 
different in Debian, Red Hat and SuSE, though there may be a 

In the end, I did it like this, based on Kathryn Hogg's suggestion:

# [^0-9] could actually be "\t", I think, 
# but I didn't want to rely on that
if grep -q -v "^Ppid:[^0-9]1$" /proc/$$/status 
then
        echo not run by init
fi

> Hope that helps,

Yes, it did. 
Thanks a lot,

dominik

PS: I cc'ed you, Wolfgang, because this really belongs in techtalk. 
Hope that's okay.