my $timeout = timed_system_call("/subprocess_a.rb", 3);
if ($timeout == 0) {
  print "success\n";
}
else {
  print "timed out\n";
}

sub timed_system_call {
    my $command = shift;
    my $timeout = shift; # seconds

    my $alarm = 0;
    eval {
        local $SIG{ALRM} = sub {$alarm = 1; kill -15, $child_pid;};
        alarm $timeout;
        system($command);
        alarm 0;
    };
    die $command . " failed with " . $@ if $@ && $alarm != 1; #if alarm is not 1, then something else caused exit e.g(ctrl-c)
    alarm 0;
    return $alarm;
}