I'm mostly using text files at the moment: I have a 'global' notes file in my home directory and then sometimes project specific notes in project directories.

I'm mostly using text files at the moment: I have a 'global' notes file in my home directory and then sometimes project specific notes in project directories. My .envrc in project directories prints the project-specific notes file when I cd into there. I have aliases and scripts that make adding a line to a file easy: m foobar # (m for memo) appends "* foobar" to my global notes. t foobar # (t for task) appends "o foobar" to it (the `o` I replace with an x when it's done) There's an alias to print the notes file and one to edit it. The notes file is synced bidirectionally to a server from my laptop. My android phone is doing the same sync. The phone displays the notes in a widget which lets me edit it with one tap. This way I can add notes from the command line and they get synced to my phone. When I edit them on my phone they get synced back.