<p>I want:
all links which not contained filename (not .html, .jpg, .png, .css) redirect with state 301 to directory, for example: <a href="http://mysite.com/article" rel="nofollow noreferrer">http://mysite.com/article</a> -> <a href="http://mysite.com/article/" rel="nofollow noreferrer">http://mysite.com/article/</a>
But <a href="http://mysite.com/article/article-15.html" rel="nofollow noreferrer">http://mysite.com/article/article-15.html</a> not redirects.
What regulat expression I must write to .htaccess for adding slash to virtual directories?</p>

Clarification needed:
Given the url:
http://server/path/file
Does that get redirected to:
http://server/path/
Or does it get redirected to:
http://server/path/file/
As in: Do you want the redirects to go to the parent path, or do you just want to add a slash and assume directory out of the current path?