$cmd="$scriptsdir/process_tar.pl $file >> /tmp/testlog &";                                        
$pid=open(PID,"|$cmd");
if(pidrunning($pid){
     print "PID $pid is running";
}else{
     print "PID $pid is not running";
}

# check if process is running
sub pidrunning{
        ($pid)=@_;
        $exists = kill 0, $pid;
        return $exists;
}