A complete primer on the whys and hows of todo.txt.

The first and most important rule of todo.txt:

A single line in your todo.txt text file represents a single task.

Plain text is software and operating system agnostic. It's searchable, portable, lightweight, and easily manipulated. It's unstructured. It works when someone else's web server is down or your Outlook .PST file is corrupt. There's no exporting and importing, no databases or tags or flags or stars or prioritizing or insert company name here-induced rules on what you can and can't do with it.

Using special notation in todo.txt, you can create a list that's sliceable by 3 key axes.

Your todo list should be able to tell you what's the next most important thing for you to get done - either by project or by context or overall. You can optionally assign tasks a priority that'll bubble them up to the top of the list.

The only way to move a big project forward is to tackle a small subtask associated with it. Your todo.txt should be able to list out all the tasks specific to a project.

In order to move along a project like "Cleaning out the garage," my task list should give me the next logical action to take in order to move that project along. "Clean out the garage" isn't a good todo item; but "Call Goodwill to schedule pickup" in the "Clean out garage" project is.

Getting Things Done author David Allen suggests splitting up your task lists by context - ie, the place and situation where you'll work on the job. Messages that you need to send go in the @email context; calls to be made @phone, household projects @home.

That way, when you've got a few minutes in the car with your cell phone, you can easily check your @phone tasks and make a call or two while you have the opportunity.

This is all possible inside todo.txt.

Your todo.txt is a plain text file. To take advantage of structured task metadata like priority, projects, context, creation, and completion date, there are a few simple but flexible file format rules.

Philosophically, the todo.txt file format has two goals:

• The file contents should be human-readable without requiring any tools other than a plain text viewer or editor.
• A user can manipulate the file contents in a plain text editor in sensible, expected ways. For example, a text editor that can sort lines alphabetically should be able to sort your task list in a meaningful way.

These two goals are why, for example, lines start with priority and/or dates, so that they are easily sorted by priority or time, and completed items are marked with an x, which both sorts at the bottom of an alphabetical list and looks like a filled-in checkbox.