Introduction to org-mode

A GNU Emacs major mode for keeping notes, authoring documents, computational notebooks, literate programming, maintaining to-do lists, planning projects, and more — in a fast and effective plain text system.

Perhaps the description above tells you nothing, but org-mode is one of the start packages of emacs. Its aim is to allow you to write in plain text (not an enriched, private, enclosed format), and enhance the experience by recognizing patterns and provide actionable, according to the pattern.

Let's dive into it.

Structure of the document

When we want to organize a document, headings are a mandatory tool.

In suite software, we have to switch back and forward using the mouse or keyboard shortcuts (in LibreOffice the first three levels are bind to Cntl+1, Cntl+2 and Cntl+3):

In org-mode text lines that start with asterisks followed by a space, are recognized as headers. The level of the header is determined by the number of asterisks!

* This is a header of level 1

Here I write some text under the first header

** Level 2 header

Which is under the previous level 1 header.

* Another level 1 header

Useful tricks

Fast outline

Situation

You are brainstorming with your collaborators, about the structure of a project, and you'd like a tool to quickly build and modify the outline structure.

Solution

Using org-mode you can do that!

Pressing Alt+Enter (in emacs its is customary to denote the Alt key by the symbol M, and Enter by Ret, i.e. pressing M-Ret) creates a header of the previous level. If there is no previous level, it creates a level 1 header.
Pressing M-UpArrow and M-DownArrow move the header you are editing up/down the "list", to reorder the outline. It carries all the sub-content in the process.
Pressing M-LeftArrow and M-RightArrow promote or demote the current heading.

Cycling view

Situation

Your brainstorming went wild, and your team and you wrote down a large (org) document with ideas. How to gain the great picture?

Solution

You might toggle the view using the keybinding S-TAB to see only the first level headers (OVERVIEW), only the headers (CONTENTS), or the whole document (SHOW ALL).

If you use TAB while placed in the first asterisks of a header, you will toggle the view restricted to the current header. In this case the views are FOLDED, CHILDREN and SUBTREE.

Sparse trees

Situation: You'd like to focus on the ideas related to a certain task or key-word.
Solution: The feature called sparse trees, bind to the keybinding C-c / (Cntl+c /), allows you to do just that… you might use regular expressions!

Lists

List are a very useful tool to give structure to our ideas. In \(\LaTeX\) there are three environments of type list: itemize, enumerate and describe. Similarly, in HTML there are ordered and unordered list (<ol> and <ul>).

In org-mode we inherit the three versions in \(LaTeX\).

Example of unordered list:
- This is an item
- And another
- the third one

Example of ordered list:
1. This is an item
2. And another
3. the third one

Example of description list:
- Languages :: English, Spanish, Italian
- Libraries :: =numpy=, =pandas=, =scikit-learn=

Useful features

If you write a list item (of whatever type), the keybinding M-RET generates a new item of the same type.
List's items are sorted, promotes or demotes using the same keybinding as headers. In the case ordered list, the numbering is managed automatically.
While you're editing an item, the keybindings S-LeftArrow and S-RightArrow change the type of bullet. It might toggle between ordered and unordered list.