update: Here is a start

package ReadOneWriteOtherone;
use strict;
use warnings;
sub TIEHANDLE {
    my( $self, $in, $out ) = @_;
    $self = bless { in => $in, out => $out}, $self;
    return $self;
}

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

    
sub READLINE {
    my $self = shift;
    $self = $self->{in};
    readline $self;
}

sub CLOSE {
    my $self = shift;
    close $self->{in};
    close $self->{out};
}

1;

package main;

unless( caller ){

    tie *BLOG => ReadOneWriteOtherone => \*STDIN, \*STDOUT or die "Cou
+ldn't tie BLOG : $!";
    print tied(*BLOG),$/;
    print tied(*BLOG)->{in},$/;
    print tied(*BLOG)->{out},$/;
    print "Enter some input buddy and hit enter : $/";
    print BLOG "You entered: ", scalar <BLOG>;
}

__END__

$$ perl ReadOneWriteOtherone.pm
ReadOneWriteOtherone=HASH(0x1abf1a4)
GLOB(0x1ab7f34)
GLOB(0x1ab5054)
Enter some input buddy and hit enter :
Hi there
You entered: Hi there
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