Over the time I have collected quite a few ebooks mostly in EPUB format. I like to have my collection as files as we are a family using different devices and thus do not want to tie them up to a single application.
As the time went by the desired books was harder and harder to find due to inconsistent naming and also there was a lot of duplicates.
To solve this problem I wanted to be able to name the files by author, then title just the same way my physical books are organised on the shelf (and my records, and my mp3 files). To accomplish this I wrote a small program that does exactly that and I would like to share it with you here
https://github.com/SeniorWizard/ebook-renamer
WARNING: This tool is not for use on an actual calibre library, use on a calibre library will damage your library
As is the tool works great for me and my needs, I have tested it on various platforms and use it myself on a weekly basis. It may not suit your needs though, but feel free to suggest changes or improvements if you like it or find it useful.