Open file, write to file, save file as a zip and stream to user for download

I'd like if someone could give me some advice on creating this script, which I will add to the existing plug-in (see code below) script below.

So what I have now (with the script below) is a means to insert a predefined set of defaults into the wordpress site. What I'm wanting to add, is a helper utility, activated by a button or link that just reads "Copy Settings", that will take a site's existing settings (the sb2_options), write that to a file, then package the resulting file, along with the original file into a new zip file that essentially becomes a custom copy of the original plug-in for use in another site.

So the code needs to take an existing .php file containing the static code, open it up for writing, then insert all the name/value pairs from the wordpress options table matching a specific prefix (for example, all my custom options are prefixed with "sb2_"). Once it's done this, it would save the resulting file as "plugin.zip", for example and stream it to the user for download.

Here is the code that I have now, which sets up the site's defaults...

<?php
/**
 * Plugin Name: my plugin
 * Description: Sets up your sites defaults.
 * Version: 1.0
 */

function sb2_plugin_init() 
{

    if ( get_option( 'sb2_plugin' ) == "") 
    {

        //Begin Insert List here. Open the file and write out all the name value pairs, just like in the example.

        //Option 1",
        $sb2_option1 = "test";

        //Option 2",
        $sb2_option2 = "test";


        //Option 1",
        $sb2_option3 = "test";

        //End insert list here

        //update site defaults
        update_option('sb2_option1', sb2_option1);
        update_option('sb2_option2', sb2_option2);
        update_option('sb2_option3', sb2_option3);
        //etc


        // Create post objects
        $my_post = array();
        $my_post['post_title'] = 'Main Blog Post Title';
        $my_post['post_content'] = 'Main Blog Post Content';
  开发者_如何学运维      $my_post['post_type'] = 'post';

        //TODO >>> NEED TO MAKE THE POST STICKY

        // Insert the post into the database
        wp_insert_post($my_post);

        wp_cache_flush();
        update_option('sb2_plugin', "1");
    }
}

add_action( 'init','sb2_plugin_init');

Reading and writing to file shouldn't be difficult for you but here is a good way to create zip files.