Markdown

Markdown is a very simple set of rules to write text. It is based on the way we used to write emails or text in general before we could use fancy HTML for that. If you have every used paper and pencil to write notes it will also be familiar to you.

For example you probably draw a line under the title and subtitles of your text. You probably put some kind of a mark in front of a list of items or you numbered them if you wanted to put more emphasize on the order.

In email messages we used to put stars around words we wanted to emphasize

Title
----

* Item A
* Item B
* Item C


1. First
2. Second
3. Third

Word to be *emphasized*.

In 2004 John Gruber took all these little practices, collected them and called the whole set and created a program that could convert text using this syntax to fancy HTML. The program was called Markdown. See the Wikipedia article about Markdown for more information.

Various systems adopted and extended the original set of rules. When GitHub started to use it for various purposes it created a definition called GitHub flavored Markdown. It is used in many place on GitHub. Not only for GitHub pages, but also in the documentation of projects, in commit messages, issues, pull-requests and more.