How to get PID in backgrounded /bin/sh while loop?

[Skip Montanaro]

Given the small shell script:

    #!/bin/sh

    ... do some stuff ...

    while true ; do

	... do some loopy stuff ...

    done &

how do you discover the process id of the backgrounded while loop process?

A colleague suggested I write a small C program that just calls getppid(2),
but that is overkill for the situation I have at hand. I've tried various
combinations of quoting $$, evaling things containing it, and so on, but
nothing yields helpful results. $! is undefined within the loop.



--
Skip (montanaro at crdgw1.ge.com)