This is the code used in .htaccess,
RewriteRule ^([A-Za-z0-9-]+)/([A-Za-z0-9-]+)/?$ /blog/index.php?a=$1 [NC,L]
I want to apply it on a particular directory, I can't apply this rule, but currently it redirect not found urls of whole website to domain/blog/index.php
Use RewriteCond. When ever you want to apply a Rule to a specific condition.
For example,
# Include in the next line all folders to include
RewriteCond %{REQUEST_URI} (folder1|folder2|folder3) [NC]
RewriteRule ^([A-Za-z0-9-]+)/([A-Za-z0-9-]+)/?$ /blog/index.php?a=$1 [NC,L]
or the other way around by adding a !
# Include in the next line all folders to exclude
RewriteCond %{REQUEST_URI} !(folder1|folder2|folder3) [NC]
RewriteRule ^([A-Za-z0-9-]+)/([A-Za-z0-9-]+)/?$ /blog/index.php?a=$1 [NC,L]
Also, keep in mind that in some cases Wordpress overights the htaccess file
In some cases adding the custom stuff to a block prevents that but not always. It depends on what plugins are in use.
## BEGIN - My Custom Redirects
<IfModule mod_rewrite.c>
.....
</IfModule>
## END - My Custom Redirects