use strict;
use warnings;

open ( my $foo, '>&=', 1 );
close( STDOUT );
print STDOUT "foo!\n";
print $foo "foo!\n";

open ( my $bar, '>&=', $foo );
close $foo;
print $foo "foo!\n";
print $bar "bar!\n";

open ( my $baz, '>', 'files/baz' );
open ( my $quux, '>&=', $baz );
close $baz;
print $quux "quux!\n";

open ( $baz, '>>', 'files/baz' );
open ( $quux, '>>&=', $baz );
close $quux;
print $baz "baz!\n";

open ( my $prefork, '>', 'files/prefork.txt' );

if ( my $kidpid = fork ) {
    my $deadkid = wait();
    print $prefork "child was pid $deadkid, which thankfully matches $kidpid (we'd be worried if it didn't)\n";
} elsif ( defined $kidpid ) {
    for ( 0..20 ) {
        open ( my $postfork, '>>&=', $_ );
        close $postfork;
        print $postfork "Whee!\n";
    }
    print $prefork "Dupes are just copies!\n";
} else {
    print "I couldn't fork!\n";
}