# Markdown: Syntax

### Philosophy

Markdown is intended to be as easy-to-read and easy-to-write as is feasible.

Readability, however, is emphasized above all else. A Markdown-formatted
document should be publishable as-is, as plain text, without looking
like it's been marked up with tags or formatting instructions. While
Markdown's syntax has been influenced by several existing text-to-HTML
filters -- including [Setext](http://docutils.sourceforge.net/mirror/setext.html), [atx](http://www.aaronsw.com/2002/atx/), [Textile](http://textism.com/tools/textile/), [reStructuredText](http://docutils.sourceforge.net/rst.html),
[Grutatext](http://www.triptico.com/software/grutatxt.html), and [EtText](http://ettext.taint.org/doc/) -- the single biggest source of
inspiration for Markdown's syntax is the format of plain text email.

## Block Elements

### Paragraphs and Line Breaks

A paragraph is simply one or more consecutive lines of text, separated
by one or more blank lines. (A blank line is any line that looks like a
blank line -- a line containing nothing but spaces or tabs is considered
blank.) Normal paragraphs should not be indented with spaces or tabs.

The implication of the "one or more consecutive lines of text" rule is
that Markdown supports "hard-wrapped" text paragraphs. This differs
significantly from most other text-to-HTML formatters (including Movable
Type's "Convert Line Breaks" option) which translate every line break
character in a paragraph into a `<br />` tag.

When you *do* want to insert a `<br />` break tag using Markdown, you
end a line with two or more spaces, then type return.

### Headers

Markdown supports two styles of headers, [Setext] [1] and [atx] [2].

Optionally, you may "close" atx-style headers. This is purely
cosmetic -- you can use this if you think it looks better. The
closing hashes don't even need to match the number of hashes
used to open the header. (The number of opening hashes
determines the header level.)

### Lists

Markdown supports ordered (numbered) and unordered (bulleted) lists.

Unordered lists use asterisks, pluses, and hyphens -- interchangably
-- as list markers:

*   Red
*   Green
*   Blue

is equivalent to:

+   Red
+   Green
+   Blue

and:

-   Red
-   Green
-   Blue

Ordered lists use numbers followed by periods:

1.  Bird
2.  McHale
3.  Parish

It's important to note that the actual numbers you use to mark the
list have no effect on the HTML output Markdown produces. The HTML
Markdown produces from the above list is:

If you instead wrote the list in Markdown like this:

1.  Bird
1.  McHale
1.  Parish

or even:

3. Bird
1. McHale
8. Parish

List items may consist of multiple paragraphs. Each subsequent
paragraph in a list item must be indented by either 4 spaces
or one tab:

1.  This is a list item with two paragraphs. Lorem ipsum dolor
    sit amet, consectetuer adipiscing elit. Aliquam hendrerit
    mi posuere lectus.

    Vestibulum enim wisi, viverra nec, fringilla in, laoreet
    vitae, risus. Donec sit amet nisl. Aliquam semper ipsum
    sit amet velit.

2.  Suspendisse id sem consectetuer libero luctus adipiscing.

### Emphasis

Markdown treats asterisks (`*`) and underscores (`_`) as indicators of
emphasis. Text wrapped with one `*` or `_` will be wrapped with an
HTML `<em>` tag; double `*`'s or `_`'s will be wrapped with an HTML
`<strong>` tag. E.g., this input:

*single asterisks*

_single underscores_

**double asterisks**

__double underscores__

~~double tilted~~