Help witha redirect

I'm not sure if this is possbile but I have a store that has changed some of its urls

here is the old type

http://www.mysite.com/productscategories

Here is the new

http://www.mysite.com/products_categories

No I prefer the new but I have 10000s of links pointing to the old

I have about 80 categories like this.

Can I do some kind of redirect from the old url to the new?

I'm more than happy to manually type each category out if necessary but I have no idea how to do it and would this amount of redirects cause lag on the server?

Advice would be apprecaited

 

This is 301 redirect - put in the root of www.mysite.com in file named .htaccess
RewriteEngine On
RewriteBase /
RewriteRule ^productscategories$ /products_categories [R=permanent,L]

same with php - put this at the very top in the file that handles productscategories
<?php
header( "HTTP/1.1 301 Moved Permanently" );
header( "Location: products_categories" );
die();
?>

 

That is very kind of you and I will begin to implement these changes right away

Thanks a lot

 

Ok didn't quite work as hoped - here is what I put


RewriteRule ^computersystems-c-22.html$ /computer-systems-c-22.html [R=permanent,L]

I can still visit the link computersystems which I was expecting it to go to computer-systems

Perhaps its has soemthing to do with the additiona -c-22.html which I did not mention previously?

Thanks a lot

 

Where is computersystems-c-22.html? In the root dir of your site or in some subfolder?
Is computersystems-c-22.html static html page or already dynamically rewritten?

 

It was already rewritten I believe and it resides in the root of the store.

Its an oscommerce store and computersystems and computer-systems go to the same place as I am led to believe the 22 is the important part rather than the text so anytext-c-22.html will go to the same place.

Hope this makes sense,

Thanks

I

 

Can anyone help?

Thanks

 

Than you need a change in htaccess
Post you htaccess file here