okay... and so i have this css bundler, while using link that follows:

http://www.example.com/min/?b=wp-content/themes/mytheme&f=style.css,boxes.css,mods.css,scripts.css

Parameter b may be the css folder url and parameter f may be the css files to obtain.

However, to help my cache, I would like the question mark gone. If at all possible, something similar to:

http://www.example.com/min/b=wp-content/themes/mytheme&f=style.css,boxes.css,mods.css,scripts.css

I attempted the next:

RewriteEngine On
RewriteRule ^/([^/\.]+)/?$ index.php?b=$1 [L]

Obviously, It didn't work.

Your rules are likely to loop, you can test adding an ailment before your rule to ensure that it appears such as this:

RewriteEngine On
RewriteCond %{REQUEST_URI} !^/index.php
RewriteRule ^/([^/\.]+)/?$ index.php?b=$1 [L]

However it appears, according to your example Web addresses, you would like something a lot more like this:

RewriteRule ^min/b=(.*)$ index.php?b=$1 [L]

This appears like a unique factor to complete where you need to eliminate ? from query string but wish to keep ampersand i.e. &.

Anyway if that is what you want you'll be able to put this code inside your .htaccess:

Options +FollowSymLinks -MultiViews
RewriteEngine on

RewriteRule ^min/b=([^;]*);f=(.*)$ min/?b=$1&f=$2 [L]

This rule will internally redirect http://www.example.com/min/b=wp-content/themes/mytheme;f=style.css,boxes.css,mods.css,scripts.css to http://www.example.com/min/?b=wp-content/themes/mytheme&f=style.css,boxes.css,mods.css,scripts.css