Taskpaper. There are vim, atom, emacs, and sublime text plugins to support the format, but I use the official Taskpaper app. I also have a handful of scripts th

Taskpaper. There are vim, atom, emacs, and sublime text plugins to support the format, but I use the official Taskpaper app. I also have a handful of scripts that I use to help manage the file, including an any.do-like daily review in a terminal (i.e. find all the overdue stuff and for each one, prompt to either mark as complete or assign a new due date or delete it; same with @today and some others). I use a separate file for an inbox, and part of the daily review is moving each of the inbox tasks to an appropriate project list in my main tasks file. I use IFTTT and the DO Note app to append new tasks into my inbox file, and I have a couple other triggers set up (for instance, a Github project of mine will drop a task into my inbox when a PR is opened to go review the PR -- this is much less distracting than an email notification or similar).