Remove Slug from CPT URLs

remove-slug.php

//Removes Slugs from CPT URLs

function na_remove_slug( $post_link, $post, $leavename ) {

    if ( 'linked_article' != $post->post_type || 'publish' != $post->post_status ) {
        return $post_link;
    }

    $post_link = str_replace( '/' . $post->post_type . '/', '/', $post_link );

    return $post_link;
}
add_filter( 'post_type_link', 'na_remove_slug', 10, 3 );