self destruct subprocess in while loop (Bash) - bash

Question

I am trying to tail a file periodically. Problem is that i must somehow kill the last process in the event of a ctrl+c or sudden closure of terminal, else tail process will remain running.
1.The following script will work, but last process might remain open if session is terminated before kill.
#cat test.sh
echo "Choose the polling interval: "
read interval
while :
do
tail -f -n0 /var/log/messages &
pid=$!
sleep "$interval"
kill "$pid"
done
Output:
#./test.sh
Choose the polling interval:
2
./test.sh: line 9: 8263 Terminated tail -f -n0 /var/log/messages
./test.sh: line 9: 8265 Terminated tail -f -n0 /var/log/messages
Ctrl^C.
/test.sh: line 9: 8267 Terminated tail -f -n0 /var/log/messages
#ps auxfww | grep [t]ail | wc -l
1
2.If i try to make the killing in background, i get many errors as seen bellow.
#cat test_bg.sh
echo "Choose the polling interval: "
read interval
while :
do
tail -f -n0 /var/log/messages &
pid=$!
(sleep "$interval" ; kill "$pid") &
done
Output:
#./test_bg.sh
Choose the polling interval:
2
tail: inotify cannot be used, reverting to polling: Too many open files
........
tail: inotify cannot be used, reverting to polling: Too many open files
How can i kill last process in the event of a sudden interruption?

Answer 1

I managed to make it work with wait like this:
echo "Choose the polling interval: "
read interval
while :
do
echo "starting tail"
tail -f -n0 /var/log/messages &
pid=$!
echo "pid is $pid"
echo "checking ps for tail"
ps -ef | grep $pid
echo "checked ps for tail"
(sleep "$interval" ; kill "$pid") &
killpid=$!
echo "counting $interval seconds"
sleep $interval
echo ""
echo "killpid is $killpid"
wait $killpid
echo ""
echo "$interval seconds have passed"
echo "killpid $killpid should be dead now"
echo ""
echo "checking ps for kill"
ps -ef | grep $killpid
echo "checked ps for kill"
echo ""
echo "tail pid $pid should be dead now"
echo "rechecking ps for tail"
ps -ef | grep $pid
echo "rechecked ps for tail"
echo ""
done