Script to display the process IDs of docker container processes and subprocesses

watchpids.sh

#!/bin/bash
pidlist() {
	local thispid=$1
	local fulllist=
	local childlist=
	childlist=$(ps --ppid $thispid -o pid h)
	for pid in $childlist
	do
		fulllist="$(pidlist $pid) $fulllist"
	done
	echo "$thispid $fulllist"
}
dockerpids() {
	local fulllist=
	local dockerpids="$(pidof docker-containerd-shim)"
	for p in ${dockerpids}
	do
		for q in $(ps --ppid $p -o pid h)
		do
			fulllist="$(pidlist $q) $fulllist"
		done
	done
	echo "$fulllist"
}
ary=($(dockerpids))
DOCKER_PIDS=${ary[@]}
ps -Ho etime,pid,ppid,user,cmd --pid ${DOCKER_PIDS// +/,} 2> /dev/null

pidlist provided from https://superuser.com/a/384913/38868