mod_rewrite with nested .htaccess files - regex

Question

I have made an .htaccess to my root directory for creating a subdomain level, assume it is sub.domain.ex that redirect to domain.ex/deb/
RewriteEngine On
RewriteBase /
RewriteCond %{HTTP_HOST} sub.domain.ex
RewriteCond %{REQUEST_URI} !deb/
RewriteRule ^(.*)$ /deb/$1 [L]
and this works well.
Now, I go to /deb/ and create another .htaccess with the following
RewriteEngine on
RewriteRule ^([^/]+)/ /deb.php?app=$1 [NC]
the deb.php is a file that prints the argument "app".
It works but only if i call http://sub.domain.ex/something/ (note the slash at the end). It only works with a final slash, if I remove it, it doesn't and I want it to work without final slash.
So I change the rule into ^([^/]+) but now I have 500 Apache internal error.
The regex coaches are by my side with the selection, maybe I'm missing something.
Thanks
UPDATE
I'm runinng mad. Mybe is wrong to put one .htaccess in the root for creating se 3th sublevel doman and the .htacces in the other directory? Because I'm ttrying some trick.
I use this rule
RewriteEngine on
RewriteRule ^([^/]+)/ deb.php?app=$1 [NC]
in the .htacces of the /deb directory and made a print_r($_GET); and called index.php. So the redirectory doesn't work at all if it forward me on the index.php of the cydia sublvel and doesn't take the /deb/deb.php!!!
Recap.
my dir structure is this:
/htdocs/ -> the root of the main domain level like www.example.com
---index.php -> home file of www.example.com
/htdocs/deb -> the root directory of the 3th sublevel domain (subdomain.example.com ->
---index.php
---deb.php
So the .htaccess for the 3th level domain is the in /htdocs./htaccess and described as before.
The other .htaccess for "beautify" the link is in the /htdocs/deb/.htaccess. I want that when you go to subdomain.domain.com/someText it transform to deb.php?app=someText
Now i tryed go to subdomain.domain.com/deb.php....WTF!? the deb.php is in /htdocs/deb/deb.php
Home is clear

Answer 1

This works fine for me, at least, assuming I understood everything you wanted.
In /htdocs/.htaccess:
RewriteEngine On
RewriteCond %{HTTP_HOST} =sub.domain.ex
RewriteCond %{REQUEST_URI} !^deb/
RewriteRule ^(.*)$ /deb/$1
In /htdocs/deb/.htaccess:
RewriteEngine On
RewriteBase /deb/
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^([^/]+)/?$ deb.php?app=$1
RewriteRule !^deb.php index.php
Edit: I updated the second file's contents to reflect your additional requests. You should remove the /? if you don't want them to be able to go to sub.domain.ex/something/ -> deb.php?app=something.

Answer 2

I could be wrong, but in the second .htaccess you should check that the url wasn't yet rewrited with "/deb.php"
So something like
RewriteCond %{REQUEST_URI} !deb\.php
RewriteRule ^([^/]+) /deb.php?app=$1 [NC]

Answer 3

You rewrite rule should be
RewriteRule ^(.*)$ deb.php?app=$1 [L,QSA]
That's a common pattern used in CMSs like Drupal

Answer 4

I think there is some kind of rescrctions to my host. It's impossible. I tried all kind of goo (for a regexcoach) for matching the correct group and there is nothing else the 500 error apache.
The only way to get this to work is use tu parameters
with this ^app/([^/]+) /deb.php?app=$1 and calling with sub.domain.com/app/nameTest and this is working with or without the end backslash.
Of you get some advice for getting rid of this, please let me know.
bye