No, IPC::Open2 and IPC::Open3 are used if you want to open 2 or 3 pipes to the same process. (STDIN, STDOUT, STDERR). In your case, I'd do something like:

    open my $in  => "zcat $file |" or die;
    open my $out => "| more" or die;
    while (<$in>) {
        # do something.
        print $out $_ or die;
    }
    close $in  or die;
    close $out or die;
[download]

Abigail