I have an idea to do an app and no means our knowledge to build.
If developer willing to work on an open source free app with root privileges please reply or pm.
This is for a free app and if it makes it to play store that's fine
Requirements: free, ad free, no network permissions, modify sd card, write to root.
All I have to offer that one could find themselves is an open source script that O.M.J wrote for me as a test bed. And it works.