#!/bin/bash

FROM=$1
TO=$2

cp "${FROM}" "${TO}" &
wPID1=$!
echo "$0 : copy-process, pid is $wPID1"

(for((;;)); do stat -c '%s' "${TO}"; sleep 1; done) &
wPID2=$!
echo "$0 : filestat-process, pid is $wPID2"

wait ${wPID1} # wait for copy-process to finish
echo "$0 : copy-process is finished"
kill ${wPID2}
echo "$0 : filestat-process killed"