best way to redirect 1300 old product pages to new product pages

[madmartian]

I have googled this topic but I am not sure which method to use. I have 1300 product pages to redirect to new prestashop product pages. Here is an example:

 

Old:

www.mydomain.com/6pack.htm

 

To:

www.mydomain.com/prestashop/336-bouncing-eyeballs-6-pack.html

 

I know from searching that I want a 301 redirect for each product page. I see that I could do that easily in the .htaccess file, but that means 1300 entries in the file, which I'm afraid could slow server response or cause some other issue. I also found I could use a page-level "refresh" with delay set to 0, but that is not always interpreted as a 301 and is not as good for search engines. There were other methods involving code, but I was not clear on how to implement them. I'm on a linux server going from one html page to another. The page name is different, so I can't just redirect the root using the "same file name" method. Also, I can't blanketly redirect all files in a folder since not all files are product files in the old folder. So what is my best choice here?

 

Note that I can rewrite all 1300 old product files with the proper redirects in seconds since I already wrote a program to do that. I could do the same to create the commands for .htaccess if that ends up being the way to go. I can also adjust my program to replace each old webpage content with code if I know the code to use. I have a file with the "from" and "to" URLs to feed to my program.