I recently downloaded and installed a new theme for Ubuntu which I'm generally happy with. The only problem is getting the new icons to associate with specific file-types. To take one example, all mp3 files are showing as a generic blank white file instead of the correct new mp3 icon available for that purpose.
At the moment the only way I know in Linux to change an icon for an individual file is to display its properties, then click on its shown icon, which then brings up the Nautilus path that I can then wade through to the relevant svg file. Once I click on that file the correct icon is finally shown. That method's fine to change the icons for a few files. But when I have to do that for maybe thousands of files there must be an easier method.
I've looked on the Web to find a more efficient means of doing this and all I see is advice to look at the mime types file to ensure there is an entry for the file type/s. But having established that then what do I do?