#!/usr/bin/env perl -l

use strict;
use warnings;
use constant SLEEP_TIME => 20;

my $pid = fork;
die "Can't fork()" unless defined $pid;

if ($pid) {
    local $SIG{TERM} = sub {
        print "Parent received signal: @_";
        die "$$ committing suicide!\n";
    };  

    {
        local $SIG{TERM} = sub {
            print "Parent received signal: @_";
            print "$$ committing infanticide!";
            kill TERM => $pid if kill 0 => $pid;
        };

        print "Parent: $$; Child: $pid";

        print "Waiting on child ...";

        waitpid($pid, 0);
    }

    print "Child terminated.";

    print "$$ resting ...";

    sleep SLEEP_TIME;

    print "$$ rested and exiting.";
}
else {
    print "Child: $$";

    local $SIG{TERM} = sub {
        print "Child received signal: @_";
        die "Child died via signal handler.\n";
    };

    sleep SLEEP_TIME;

    exit;
}

##</code><code>##

Parent: 36789; Child: 36790
Waiting on child ...
Child: 36790
Child terminated.
36789 resting ...
36789 rested and exiting.

##</code><code>##

Parent: 36797; Child: 36798
Waiting on child ...
Child: 36798
Parent received signal: TERM
36797 committing infanticide!
Child received signal: TERM
Child died via signal handler.
Child terminated.
36797 resting ...
Parent received signal: TERM
36797 committing suicide!

##</code><code>##

Parent: 36835; Child: 36836
Waiting on child ...
Child: 36836
Child received signal: TERM
Child died via signal handler.
Child terminated.
36835 resting ...
Parent received signal: TERM
36835 committing suicide!