org-mode is a toolkit for you to organize things. It is part of Emacs.
Its website says:
Your life in plain text: Org mode is for keeping notes, maintaining TODO lists, planning projects, and authoring documents with a fast and effective plain-text system.
To highlight a few things:
You can use org-mode to maintain todo lists. items can be scattered across org-mode files, contain attachments, have tags, deadlines, schedules. There is a convenient “agenda” view to show you what needs to be done. Items can repeat.
You can also use it to write documents. org-mode has special features for generating HTML, LaTeX, slides (with LaTeX beamer), and all sorts of other formats. It also supports direct evaluation of code in-buffer and literate programming in virtually any Emacs-supported language. If you want to bend your mind on this stuff, read this article on literate devops. The entire worg site is made with org mode. As a matter of fact, so is this one; read How this site is built for more.
You can keep notes, too. With full-text search, cross-referencing by file (as a wiki), by UUID, and even into other systems (into mu4e by Message-ID, into ERC logs, etc, etc.) You can add org-roam to it to take this to the next level, too.
Links to this note
According to its website, org-roam is “a plain-text personal knowledge management system”. It is based on the popular Zettelkasten knowledge management system, or the Roam Research website. But because it layers atop org-mode and therefore Emacs, it has a lot of power that the others lack; for instance, integration with email and agendas.
Arguably the most successful platform whose code can be easily modified at runtime. Emacs presents this through the metaphor of a text editor, though the Emacs platform has been about more than that since pretty much its inception. Emacs as a platform hosts email readers, Usenet clients, web and Gopher browsers, games, terminal emulators, sftp clients, chat clients, and even a window manager. With org-mode, most of these (including the email clients) can be linked together with agendas, task lists, and personal notes to form an integrated tracking system. org-roam extends this yet further.
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