tie *STDOUT, TrapClass;

my $pid = fork();
die "" if !defined $pid;
exit 0 if $pid; # parent exits

exec "/bin/date"; # child prints to STDOUT!!

package TrapClass;

sub TIEHANDLE {
    my $class = shift;
    open(my $fh, ">out") or die;
    bless { fh => $fh }, $class;
}

sub PRINT {
    my $self = shift;
    my $fh = $self->{fh};
    print $fh @_;
}