#!/usr/bin/perl -w
use strict;
use Filter::Handle qw/subs/;

Filter \*STDOUT,
    sub { local $_ = "@_"; s/blue/red/g; $_ };

print "My house is blue.\n";
print "So is my cat, whose nose is blue.\n";

UnFilter \*STDOUT;

print "And the plane is also blue.\n";

##</code><code>##

sub PRINT {
    my $self = shift;
    my $fh = *{ $self->{fh} };
    print $fh, $self->{output}->(@_);
}

##</code><code>##

sub PRINT {
    my $self = shift;
    my $fh = *{ $self->{fh} };
    CORE::print $fh $self->{output}->(@_);
}
##</code><code>##

use subs qw(print printf);