#!/usr/bin/perl

use POSIX ":sys_wait_h";

print "process id: $$\n";
my $pid = fork;
my $FH;
unless($pid){
    setpgrp;
    exec('./script');
}
print "Child process id is: $pid\n";
for (1..5) {
    kill -9, $pid if $_ == 4;  # kill children in the 4th round
    system "ps Tf -o etime,pid,pgrp,stat,cmd";
    sleep(3);
    waitpid(-1, WNOHANG);
}