redirecting to moved site

I redirected a WordPress install at site.com/sub to appear from site.com/ root by moving index.php and .htaccess and editing require(‘./subdirectory/wp-blog-header.php’) and changing the site domain name in settings/general and this works fine.

However, until the search engiones catch up is there a way to redirect the old urls to the new, eg: site.com/sub/item135 to site.com/item135 ?

I tried adding 301 redirect to the .htaccess in root and /sub but disabled the whole site in both cases (possibly git the syntax wrong!)

Any advice most appreciated.