如何通过robots.txt文件在opencart中取消索引特定类别

Hello if i am not wrong robots.txt file will be this for opencart

User-agent: *
Disallow: /*&limit
Disallow: /*&sort
Disallow: /*?route=checkout/
Disallow: /*?route=account/
Disallow: /*?route=product/search
Disallow: /*?route=affiliate/
Allow: /

I want to de-index a category from my site so what code i use in robots.txt file to remove that category from google. Thanks.

Open /catalog/controller/product/category.php

Find this line

if ($category_info) {

On a new line after it add this

if ($category_info['category_id'] == 123) {
     header("X-Robots-Tag: noindex", true);
}

changing 123 to the category id of the one you want to stop indexing