Rewrite all files from folder to another folder - .htaccess

Question

I want redirect all requested files from folder-a to folder-b. E.g. http://www.yoursite.com/folder-a/index.php to http://www.yoursite.com/folder-b/index.php.
How can I do that? I have verified if mod_rewrite works with this code:
RewriteEngine On
RewriteRule ^google.html$ http://www.google.com/ [R=301]
The structure on the webspace is the following:
.htacces
|-folder-a
|-folder-b
But if I want my folder redirect
RewriteEngine On
RewriteRule ^/folder-a/(.*)$ http://www.yoursite.com/folder-b/$1 [L,R=301]
the redirect doesn't work if I input the following URL:
http://www.yoursite.com/folder-a/
http://www.yoursite.com/folder-a/index.php
The redirect doesn't take place. I stay on the same page ... What I'm doing wrong? I also tried it with this htaccess:
Options +FollowSymLinks
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^folder-a(.*)$ http://www.yoursite.com/folder-b$1 [L,R=301]
</IfModule>
If all this works I want to exclude some files. Eg. with this htaccess:
RedirectPermanent /folder-a/info.php /folder-b/new-info.php
Edit:
Now I tried this htaccess
redirectMatch 301 ^/folder-a/ http://www.yoursite.com/folder-b
This works, but I need something which takes the whole path and rewrite it to the new folder.
This for example doesn't work:
RewriteRule ^folder-a/(.*)$ folder-b/$1
Solution
I had an old htacess file in my folder-a so the redirect didn't worked. This is my final htaccess:
Options +FollowSymLinks
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^folder-a/excludefile1.php http://www.yoursite.com/folder-b/newnameforfile1.php [L,R=301]
RewriteRule ^folder-a/excludefile2.php http://www.yoursite.com/folder-b/newnameforfile2.php [L,R=301]
RewriteRule ^folder-a/(.*)$ http://www.yoursite.com/folder-b/$1 [L,R=301]
</IfModule>

Answer 1

You probably need to put both rules in place: one for the empty folder and one for other files, and then the catch-all at the bottom. This is not tested:
RewriteEngine On
RewriteRule ^folder-a/info.php http://www.yoursite.com/folder-b/new-info.php [L,R=301]
RewriteRule ^folder-a/ http://www.yoursite.com/folder-b/ [L,R=301]
RewriteRule ^folder-a/(.*)$ http://www.yoursite.com/folder-b/$1 [L,R=301]