I use the developer diary Devarist nowadays, which lets you store things in Markdown, and I periodically export those entries to a single local markdown file. I

I use the developer diary Devarist nowadays, which lets you store things in Markdown, and I periodically export those entries to a single local markdown file. I prefer the searching and organization (and always online) aspect of Devarist, but I don't want to lose my files either. I also include little icons that represent the category so I can visually browse and filter pretty quickly and easily as I scroll through it.