use warnings;
use strict;

use POSIX;

my $skip_end = 0;

END { print "this should print once\n" }

if (fork)
{
    print "parent\n";
    sleep 1;
}
else
{
    print "child\n";
    $skip_end ? _exit(0) : exit(0);
}

print "last line of program\n";

##</code><code>##

child
this should print once
parent
last line of program
this should print once

##</code><code>##

parent
child

##</code><code>##

child
parent
last line of program
this should print once