HikaShop

A) Go into product listings of HikaShop in the administration area and click on the "export" button. That will give a CSV with all the product data. The format of the CSV is explained here:
http://www.hikashop.com/support/support/documentation/73-hikashop-import.html

B) You can also go in the menu System>Mass actions of HikaShop and create a new mass action with an action "export a CSV file". It's possible to select the fields you want to export with that solution, and you can have it regenerate automatically with a frequency of your choosing. The format of the CSV will be similar to the first option.

C) You can also configure the HikaShop Google Products plugin via the Joomla plugins manager. That plugin will generate a XML file compatible with the
Google Products platform:
- http://www.hikashop.com/support/support/documentation/86-integration-with-google-products.html

If you need another format, you have two ways to go about it:
- You can customize the file "export" of the view "product" for your backend template via the menu Display>Views so that when you click on the "export" button of the products listing, it will generate a file with the format you want.
- You can create your own plugin to do exactly what you want, like we did for the Google Products plugin.