Display Page/Post ID

/**

 * Add Sortable Post ID Column Before Author in Admin List View

 */

function add_sortable_post_id_before_author_column($columns) {

    $new_columns = array();

    foreach ($columns as $key => $value) {

        if ($key === 'author') {

            $new_columns['post_id'] = 'ID';

        }

        $new_columns[$key] = $value;

    }

    return $new_columns;

}

add_filter('manage_posts_columns', 'add_sortable_post_id_before_author_column');

add_filter('manage_pages_columns', 'add_sortable_post_id_before_author_column');

/**

 * Make Post ID Column Sortable

 */

function make_post_id_column_sortable($sortable_columns) {

    $sortable_columns['post_id'] = 'ID';

    return $sortable_columns;

}

add_filter('manage_edit-post_sortable_columns', 'make_post_id_column_sortable');

add_filter('manage_edit-page_sortable_columns', 'make_post_id_column_sortable');

/**

 * Display Post ID in the Custom Column (No Change Needed)

 */

function display_post_id_column($column, $post_id) {

    if ($column === 'post_id') {

        echo $post_id;

    }

}

add_action('manage_posts_custom_column', 'display_post_id_column', 10, 2);

add_action('manage_pages_custom_column', 'display_post_id_column', 10, 2);