htaccess rule..not able to solve - .htaccess

Question

i am struggling to get my site htaccess work... but no luck..
below is the code
<IfModule mod_rewrite.c>
Options +FollowSymLinks
RewriteEngine On
RewriteBase /
RewriteCond %{HTTP_HOST} ^example\.com$ [NC]
RewriteRule ^(.*)$ http://www.example.com/$1 [L,R=301]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^([^/]+)/? /profile.php?username=$1 [L,NC]
</IfModule>
this works fine no issues.. but when i add something it will not work.. in following cases -
1) For example when i type example.com/dinesh it will redirect me to www.example.com (always home page instead i want it to be www.example.com/dinesh
2) now i have another users.php with two parameters the thing is when i pass one parameter it should execute this rule profile.php but when i pass two parameters then it should take me to user.php i tried so many combination but this is not working.
if any expert can give me atleast some tips that will be great.

Answer 1

As for 1), it probably doesn't have anything to do with the above rules. If /dinesh exists, you should look in there. If it doesn't exist, you should look into /profile.php, that's probably what's redirecting you to the home page.
As for 2), your rule:
RewriteRule ^([^/]+)/? /profile.php?username=$1 [L,NC]
Matches the URI: /something/else, because the regular expression doesn't have an end-of-string match. It matches the first something, and that's good enough. If you add a $ to the end, it won't match /something/else.
RewriteRule ^([^/]+)/?$ /profile.php?username=$1 [L,NC]
Or, you can place the other rule that routes to user.php before the one that routes to profile. but it's better to have the $.