htaccess - what counts as duplicates?

Question

Search Engine Optimization

site for 5 pages without cms.
trimmed ".php" from pages via htaccess.
now all pages are available at two addresses
- site.ru/cat
- site.ru/cat.php
is this considered a duplicate? what to write in robots.txt in this case?

Answer 1

You can close all .php files in robots:
Disallow: *.php
But you should only do this if you don't have any .php pages that should be in the index.
You can also use .htaccess to redirect from all name.php to name (i.e. a redirect with a url with an extension to a url without an extension). It's easy to google.