Markdown how-to

Markdown is a lightweight markup language designed for creating formatted text using a plain-text editor. Created by John Gruber and Aaron Swartz in 2004, its primary goal is readability: the source document should be as legible as possible in its unrendered form.

Today, Markdown is the standard for documentation, technical writing, and web-based communication. Because the original specification left some behaviors undefined, various "flavors" (dialects) have emerged, most notably CommonMark (a highly standardized version) and GitHub Flavored Markdown (GFM).

Core Syntax

The following elements are widely supported across almost all Markdown parsers and form the foundation of the language.

Headings

Headings are created by prefixing text with hash symbols (#). The number of hashes corresponds to the heading level (1 through 6).

# Level 1 Heading
## Level 2 Heading
### Level 3 Heading

Emphasis

Text can be styled as italics or bold using asterisks (*) or underscores (_).

Lists

Unordered lists use asterisks, pluses, or hyphens. Ordered lists use numbers followed by a period.

- Item 1
- Item 2
  - Nested Item (indent with 2 or 4 spaces)

1. First item
2. Second item

Note: In most implementations, the actual numbers used in an ordered list do not matter; the parser will automatically increment them.

Links and Images

Links and images share a similar bracketed syntax.

• Link: [Agpedia](https://agpedia.org)
• Image: ![Alt text for accessibility](https://example.com/image.png)

Blockquotes

Blockquotes are indicated by the > symbol at the start of a line.

> "Simplicity is the ultimate sophistication."
> — Leonardo da Vinci

Code

Inline code is wrapped in single backticks (`). Block code is typically indented by four spaces or, in more modern implementations, wrapped in "fences" of three backticks (```).

Extensions and GFM

Many platforms, including GitHub, add features to the core specification to support technical and collaborative workflows.

Tables

Tables are constructed using pipes (|) and hyphens (-). Hyphens define the header row, and colons within the header separator can be used for alignment.

| Feature | Support | Description |
| :--- | :---: | ---: |
| Tables | GFM | Left, center, and right aligned |

Task Lists

Task lists allow for the creation of interactive or visual checklists.

- [x] Complete the draft
- [ ] Review for clarity
- [ ] Add citations

Strikethrough

Double tildes are used to indicate deleted or corrected text.

This is ~~wrong~~ corrected.

Autolinks

GFM and many modern parsers automatically convert URLs and email addresses into clickable links without requiring special Markdown syntax.

https://example.com

Structural Rules

Paragraphs and Line Breaks

• Paragraphs: Created by separating lines of text with one or more blank lines.
• Hard Line Breaks: To force a line break within a paragraph, end a line with two or more spaces, or use a backslash (\) at the end of the line.

Horizontal Rules

Three or more hyphens, asterisks, or underscores on a line by themselves create a thematic break (<hr>).

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