Re: Cleaning up background processes

On Mon, 6 May 2024 12:08:39 -0000 (UTC), gazelle@shell.xmission.com (Kenny
McCormack) wrote in <v1ah87$l0a8$1@news.xmission.com>:

In article <20240505214609.114@kylheku.com>,
Kaz Kylheku  <643-408-1753@kylheku.com> wrote:

On 2024-05-05, Christian Weisgerber <naddy@mips.inka.de> wrote:

Is there a standard POSIX shell idiom to clean up background
processes?
>
You have a shell script that starts some background process with &.
Now you want to make sure that the background process terminates when
the shell script terminates.  In particular, when it terminates due to
special circumstances.

>
Maybe have an EXIT trap which calls wait?

 
The fundamental underlying problem here is that the EXIT trap is only
called on a "normal" exit.  In particular, it does not get called under
(at least) the following circumstances:
 
    1) User hits ^C causing the script to abort.

I'm sorry, but I've waited and nobody said anything, so
I have to ask:  Why couldn't you trap "kill -1 0" INT?

    2) Script exits via an "exec" statement.

This is true, and I can't see any way around that.

As I read it, that's what this thread is actually about.
 
This is a problem I've often grappled with and I'm convinced that there
is no universal solution.
 
Having said that, I think we are all making our own assumptions about
what the actual, underlying problem is.  Given that OP is not a newbie,
it would help a lot if he would clarify what exact situation he is
dealing with, rather than have us all guess (which is SOP when the
poster *is* a newbie).

Wish they would clarify what they meant...

--
-v