i’m not sure what you’re asking? what are you trying to achieve here?
video_shader_dir is where ALL the shaders are found, so when you use the retroarch GUI to choose one you can find them without having to navigate through your file system. you shouldn’t be changing this in retropie as it’s already configured.
video_shader_path is the path to the SPECIFIC shader you want to enable in this emulator (or ALL retroarch emulators if you’re looking at all/retroarch.cfg). you also have to set video_shader_enable = true to get this shader to load on launch.