Should I put [L] or [R=301] at end of mod_rewrite?

Currently I am using a rewrite that looks something like this

RewriteRule ^(.*)-(.*)$ index.php?c=$1&s=$2

Code (markup):

I notice other people on this forum ending the line with [L], or [R=301]., like in the following line

RewriteRule ^(.*)-(.*)$ index.php?c=$1&s=$2 [L]

Code (markup):

or

RewriteRule ^(.*)-(.*)$ index.php?c=$1&s=$2 [R=301]

Code (markup):

or both

Is there a difference or a reason for this?
thanks

 

i think (but not sure) [L] would give a 401 un authorised error and [R=301] would re-direct the visiter

 

ok so i was wrong - sorry

 

just found a cool cheat sheat that you can use for fyture reference http://www.ilovejackdaniels.com/mod_rewrite_cheat_sheet.png

 

Ok [L] is simply an optimization, and [R=301] means it is a permanent redirect.
But what if I didnt specify the [R=301]? Does it return some type of other response code?
Is is really better from a search engine perspective include the [R=301] part? (From a users perspective there is no difference that I can see)

 

It appears to me if I use a 301 redirect, the new url becomes visible in the browser url bar..(not what I want)
If I wish to use mod_rewrite to make the urls shorter, shoult I then use a 302 redirect? I am really confused now.

 

You don't need R at all. From what I understand, all you are after is SE-friendly urls which is what mod_rewrite can be used for without R directive. You'd use redirects (301 or 302) only if your pages actually changed locations and you needed to inform the search engines and site users about the change.