WordPress Multisite Copy Users from One Site to Another

I made a little plugin that let me copy users from one blog to another in WordPress multisite.¹

I thought I’d have to use switch_to or something but I didn’t. It’d be easy to expand this to do more tricks for you and have more shortcode parameters but I don’t need them so it is what it is.

function copy_users_home($atts){
 $a = shortcode_atts( array(
    'id' => '',   //copy from this site
  ), $atts );

  $copy_site_id = $a['id'];
  $the_users = get_users( 'blog_id='.$copy_site_id );
  foreach ( $the_users as $user ) {
    echo  $user->ID . '<br>';// I just like to see stuff happen sometimes
    add_user_to_blog(1, $user->ID, 'subscriber');
  }

  //add_user_to_blog($blog_id, $user_id, $role);

}

add_shortcode( 'copy', 'copy_users_home' );