From http://www.webconfs.com/how-to-redirect-a-webpage.php I’d say you can use the following configuration
Don’t redirect subfolders/files (as you wanted): www.example.com/demo/ -> www.newexampledomain.com
Options +FollowSymLinks
RewriteEngine on
RewriteRule (.*) http://www.newdomain.com/ [R=301,L]
Redirect to subfolders/files: www.example.com/demo/ -> www.newexampledomain.com/demo/
Options +FollowSymLinks
RewriteEngine on
RewriteRule (.*) http://www.newdomain.com/$1 [R=301,L]