Many design tools now feature workflows for exporting Retina images, but only for the current document; bulk conversion of assets has tended to be the role of complex command-line utilities like ImageMagick or task runners like Grunt. PhotoShop Actions can be used for batch processing, but they can be somewhat finicky to record, play back, and modify.
For designers, there’s a nice intermediate solution between using a familiar GUI and the power of a CLI: most Adobe products have had the power to run JavaScript under the hood for years. Creating a script action provides complete customisation for your project needs, and acts as a potential stepping stone to stand-alone systems like Gulp.