Apostate Café


By Joshua Ellis

Pubished:

Posted in: meaning-beauty-whimsy
Tagged as: Calepin / testing / markdown

Markdown Test

Markdown Test

Calepin is based on Pelican, which uses the Python Markdown package with the codehilite, extra, and meta extensions.

Attribute Lists

{: #someid .someclass somekey=’some values’ }

Use a hash # to set the id of an element, and a dot . to add to an element’s list of classes.

Attributes: Block Level

To define attributes for a block level element, the attribute list should be defined on the last line of the block by itself.

This is a paragraph.
{: #an_id .a_class }

Results in

<p class="a_class" id="an_id">This is a paragraph.</p>

i.e.

This is a paragraph. {: #an_id .a_class }

The exception is headers, which are only allowed on one line.

A setext style header {: #setext}
=================================

### A hash style header ### {: #hash }

Results in

<h1 id="setext">A setext style header</h1>
<h3 id="hash">A hash style header</h3>

A setext style header {: #setext}

A hash style header ### {: #hash }

Attributes: Inline Level

To assign attributes inline, give the attribute list immediately after the inline element with no whitespace.

[link](http://example.com){: class="foo bar" title="Some title!" }

The above results in the following output:

<p><a class="foo bar" href="http://example.com" title="Some title!">link</a></p>

link{: class=“foo bar” title="Some title! }

Code highlight

SheBang (with path)

If the first line of the codeblock contains a shebang, the language is derived from that and line numbers are used. If the first line contains a shebang, but the shebang line does not contain a path (a single / or even a space), then that line is removed from the code block before processing. Line numbers are used.

#!/usr/bin/python
# Code goes here ...

!/usr/bin/python

Code goes here …

Versus

#!python
# Code goes here ...

!/usr/bin/python

Code goes here …

Colons

If the first line begins with three or more colons, the text following the colons identifies the language. The first line is removed from the code block before processing and line numbers are not used.

:::python
# Code goes here ...

:::python

Code goes here …


Paragraph with normal text.

Emphasized text, also known as italic.

Strongly emphasized text, also known as bold.

Unnumbered list:

  • Paul
  • Whiteman

Numbered list:

  1. Eddie
  2. Cantor

Nested lists:

  • Bix
  • Spiritus
  • Et
    • Lasse
    • Dahlquist
      1. Hilmer
      2. Borgeling
  • Artibus
  • Beiderbecke

MarkdownExtra tests

From http://michelf.com/projects/php-markdown/extra/

Headers with IDs (note: not name)

For example

Header 1            {#header1}
========

## Header 2 ##      {#header2}

Results in

<h1 id="header1">Header 1</h1>
<h2 id="header2">Header 2</h2>

Header 1 {#header1}

Header 2 ## {#header2}

Simple tables

This

First Header  | Second Header
------------- | -------------
Content Cell  | Content Cell
Content Cell  | Content Cell

Produces

<table>
<thead>
<tr>
<th>First Header</th>
<th>Second Header</th>
</tr>
</thead>
<tbody>
<tr>
<td>Content Cell</td>
<td>Content Cell</td>
</tr>
<tr>
<td>Content Cell</td>
<td>Content Cell</td>
</tr>
</tbody>
</table>
First Header Second Header
Content Cell Content Cell
Content Cell Content Cell

Alignment test

Alignment does not work

Item Value
Computer $1600
Phone $12
Pipe $1

Span-level formatting

Function name Description
help() Display the help window.
destroy() Destroy your computer!

Definition lists

Definition lists work, but are not styled

The code

Apple
:   Pomaceous fruit of plants of the genus Malus in
    the family Rosaceae.

Orange
:   The fruit of an evergreen tree of the genus Citrus.

Results in

<dl>
<dt>Apple</dt>
<dd>Pomaceous fruit of plants of the genus Malus in
the family Rosaceae.</dd>
<dt>Orange</dt>
<dd>The fruit of an evergreen tree of the genus Citrus.</dd>
</dl>
Apple
Pomaceous fruit of plants of the genus Malus in the family Rosaceae.
Orange
The fruit of an evergreen tree of the genus Citrus.

Footnotes

Footnotes work as expected:

That's some text with a footnote.[^1]

[^1]: And that's the footnote.

Results in

<p>That's some text with a footnote.<sup id="fnref:1"><a href="#fn:1" rel="footnote">1</a></sup></p>

and later…

<li id="fn:1">
<p>And that's the footnote.&#160;<a href="#fnref:1" rev="footnote" title="Jump back to footnote 1 in the text">&#8617;</a></p>
</li>

That’s some text with a footnote.[1]

Abbreviations

Abbreviations also work. For example:

*[HTML]: Hyper Text Markup Language
*[W3C]:  World Wide Web Consortium

The HTML specification is maintained by the W3C.

Results in:

<p>The <abbr title="Hyper Text Markup Language">HTML</abbr> specification is maintained by the <abbr title="World Wide Web Consortium">W3C</abbr>.</p>

Note that abbreviations are not styled.

HTML: Hyper Text Markup Language [W3C]: World Wide Web Consortium

The HTML specification is maintained by the W3C.


Tests for common HTML elements

Paragraphs & Inline Markup

This paragraph contains elements. Up first is the anchor tag, which can occur as an a + href, or an <a> a + name, followed by an ABBR with a title value, followed by an ACRONYM with a title value, followed by a b (for bold) element, followed by a big element, followed by a Citation (cite) element, followed by a Computer code text (code) element, followed by a Deleted (del) element, followed by a Definition term (dfn) element, followed by Emphasized text (em), followed by an italics (i) element.

This next paragraph also contains elements. Up first is the <ins> element, followed by keyboard text (kbd), followed by a <mark> element, followed by a Q element and a double nested Q (a quotation inside a quotation), followed by sample text (samp), followed by a small element, followed by a span element, followed by a strike element, followed by strong text (strong), followed by text in monospace font (tt), followed by an underlined element (u), followed by a Variable element (var, compared to code), all within a containing P. In order to test subscripts and superscripts inside running text, we need constructs like x1 and H2O and Mlle and 1st, and then some mathematical notations: ex, sin2 x, and nested exponents too: ex2 and f(x)g(x)a+b+c (where 2 and a+b+c should appear as exponents of exponents).


A mechanism to upload new versions of your app

First we have to clone our repository in our server:

:::bash
cd /var/www/
git clone your_repository_url.git your_app

Then we will create a script in our server /etc/init.d/your_app that will allow us to stop/start/restart our app:

:::bash
#!/bin/bash
DIR=/var/www/your_app
PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin
NODE_PATH=/usr/local/lib/node_modules
NODE=/usr/local/bin/node

test -x $NODE || exit 0

function start_app {
  NODE_ENV=production nohup "$NODE" "$DIR/app.js" 1>>"$DIR/logs/your_app.log" 2>&1 &
  echo $! > "$DIR/pids/your_app.pid"
}

function stop_app {
  kill `cat $DIR/pids/your_app.pid`
}

case $1 in
   start)
      start_app ;;
    stop)
      stop_app ;;
    restart)
      stop_app
      start_app
      ;;
    *)
      echo "usage: your_app {start|stop}" ;;
esac
exit 0

The last part is to write a simple bash script for our development enviroment that will allows us to connect to our machine with ssh and pull changes. This is what I personally use:

:::bash
#!/bin/bash

SERVER=( 'your_hostname.your_domain.com' )
DEPLOY_PATH=/var/www/your_app
[email protected]_repository_url.git
USER=deploy

ENVIRONMENT=${1:-"production"}
REF=${2:-"master"}

trap 'test -n "$SUCCESS" || echo "  error: aborted"' EXIT
echo "* Deploying $ENVIRONMENT/$REF"

ssh $USER@$SERVER "cd $DEPLOY_PATH && \
                   git reset --hard && \
                   git checkout $REF && \
                   git pull && \
                   npm install && \
                   /etc/init.d/your_app stop"

SUCCESS=true

To deploy we just need to give execution permissions to that file (chmod +x deploy) and we are ready to go!

:::bash
git commit -am 'some changes'
git push
./deploy

JSON

:::javascript
{
  "author": "Merlin Mann",
  "default_date_format": "%B %e, %Y",
  "with_future_dates": true,
  "with_pagination": true,
  "google_analytics": "UA-xxx-nn",
  "output_source": true
}

Python

:::python
def wrapwrite(text): sys.stdout.write(text.encode('utf8'))

CSS

::CSS
* {
  font-family: 'Baskerville', 'Garamond', 'Palatino', 'Palatino Linotype', 'Hoefler Text', 'Times New Roman', serif !important;
}

hr {
  border: 10px solid red !important;
}
p {
}
body {
  background-image: url("images/back40.gif");
}
h3 {
  font-size: 60px !important;
}

HTML

:::HTML

<h1>
    yes, this
</h1>
<h2 id="newideas">
    new ideas
</h2>
<ul>
    <li>
        omnioutliner for credit cards to change
        <ul>
            <li>
                can also work with 1password and tags
            </li>
        </ul>
    </li>

</ul>

Ruby

:::ruby
require 'rubygems'
require 'chronic' # (`gem install chronic`)

if ARGV.length > 0
  input = ARGV.join(" ").strip
else
  print "Log entry: "
  input = gets.strip
end

::ruby
require 'rubygems'
require 'chronic' # (`gem install chronic`)

if ARGV.length > 0
  input = ARGV.join(" ").strip
else
  print "Log entry: "
  input = gets.strip
end


:ruby
require 'rubygems'
require 'chronic' # (`gem install chronic`)

if ARGV.length > 0
  input = ARGV.join(" ").strip
else
  print "Log entry: "
  input = gets.strip
end

Perl

:::perl

#!/usr/bin/python

import json
import datetime
import cgi
import os
import sys

user = os.getlogin()
input_filename = "/Users/%s/Library/Application Support/Google/Chrome/Default/Bookmarks" % user
# modify if necessary
output_filename = "/Users/%s/Documents/chrome-bookmarks.html" % user

:::python
>>> def hello():
        print "Hello"

You are so good looking. Lorem ipsum dolor sit amet elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. Ut wisi enim ad tation ullamcorper ut aliquip ex ea commodo consequat. Pretty fractal, right?

:::CSS
* {
  font-family: 'Baskerville', 'Garamond', 'Palatino', 'Palatino Linotype', 'Hoefler Text', 'Times New Roman', serif !important;
}

hr {
  border: 10px solid red !important;
}
p {
}
body {
  background-image: url("images/back40.gif");
}
h3 {
  font-size: 60px !important;
}

h1

h2

h3

h4

h5
h6

Lessons Learnt

  1. Don’t push the initial state to store it into the History, just use javascript for that job (or any other storage). One alternative will be use the replaceState call, but when the user clicks back/forward the javascript inside the page is executed, so, it’s simple to just load the default data from javascript.

    :::javascript
    var state = History.getState(), data = state.data;
    
    if (data === null || $.isEmptyObject(data)) {
      data = {
        // Just load your default content
      };
    }
    
  2. Keep the content simple. This allow me to scale the use of the History API really easily in the hole web team.


Functions

Functions are the base of functional languages. In Haskell they receive 0 or more arguments and always return a value. Haskell syntax for functions is really simple:

:::haskell
numCardsInAPokerDeck = 53
numCards deck = length deck
isAPokerDeck deck = (numCards deck) (==) numCardsInAPokerDeck
biggerDeck d1 d2 = if (numCards d1) > (numCards d2)
                   then d1
                   else d2

Function application is left associative.

Purity

Haskell functions are pure. This means that they cannot alter the state of the program by producing side-effects. Any pure function is also idempotent so it must return always the same result for a given set of arguments.

How does Haskell achieve purity? - There are no variables: Functions can be used to define contant values but those can’t be modified. - Immutable data types: All the builtin data types defined in Haskell are immutable. Instead of altering the state of an instance, copies representing the new one are returned.


I’m hoping that MathJax works. Let’s test it:

\(A=\{a,b,c\}\)

\(f(x)=x^{3n+1}\)

Why green?! Displaystyle? \[\int_a^b f(x)\ dx=F(b)-F(a)\]

Here is the script that I’m using:

:::Java
<script type="text/javascript"
src="http://cdn.mathjax.org/mathjax/latest/MathJax.js?config=TeX-AMS-MML_HTMLorMML">
MathJax.Hub.Config({
  extensions: ["tex2jax.js","TeX/AMSmath.js","TeX/AMSsymbols.js"],
  jax: ["input/TeX","output/HTML-CSS"],
  tex2jax: {inlineMath: [["$","$"]]}
});
</script>

Markdown

Note: This document is itself written using Markdown; you can see the source for it by adding ‘.text’ to the URL.


Overview

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, atx, Textile, reStructuredText, Grutatext, and EtText – the single biggest source of inspiration for Markdown’s syntax is the format of plain text email.

To this end, Markdown’s syntax is comprised entirely of punctuation characters, which punctuation characters have been carefully chosen so as to look like what they mean. E.g., asterisks around a word actually look like *emphasis*. Markdown lists look like, well, lists. Even blockquotes look like quoted passages of text, assuming you’ve ever used email.

Inline HTML

Markdown’s syntax is intended for one purpose: to be used as a format for writing for the web.

Markdown is not a replacement for HTML, or even close to it. Its syntax is very small, corresponding only to a very small subset of HTML tags. The idea is not to create a syntax that makes it easier to insert HTML tags. In my opinion, HTML tags are already easy to insert. The idea for Markdown is to make it easy to read, write, and edit prose. HTML is a publishing format; Markdown is a writing format. Thus, Markdown’s formatting syntax only addresses issues that can be conveyed in plain text.

For any markup that is not covered by Markdown’s syntax, you simply use HTML itself. There’s no need to preface it or delimit it to indicate that you’re switching from Markdown to HTML; you just use the tags.

The only restrictions are that block-level HTML elements – e.g. <div>, <table>, <pre>, <p>, etc. – must be separated from surrounding content by blank lines, and the start and end tags of the block should not be indented with tabs or spaces. Markdown is smart enough not to add extra (unwanted) <p> tags around HTML block-level tags.

For example, to add an HTML table to a Markdown article:

This is a regular paragraph.

<table>
    <tr>
        <td>Foo</td>
    </tr>
</table>

This is another regular paragraph.

Note that Markdown formatting syntax is not processed within block-level HTML tags. E.g., you can’t use Markdown-style *emphasis* inside an HTML block.

Span-level HTML tags – e.g. <span>, <cite>, or <del> – can be used anywhere in a Markdown paragraph, list item, or header. If you want, you can even use HTML tags instead of Markdown formatting; e.g. if you’d prefer to use HTML <a> or <img> tags instead of Markdown’s link or image syntax, go right ahead.

Unlike block-level HTML tags, Markdown syntax is processed within span-level tags.

Automatic Escaping for Special Characters

In HTML, there are two characters that demand special treatment: < and &. Left angle brackets are used to start tags; ampersands are used to denote HTML entities. If you want to use them as literal characters, you must escape them as entities, e.g. &lt;, and &amp;.

Ampersands in particular are bedeviling for web writers. If you want to write about ‘AT&T’, you need to write ‘AT&amp;T’. You even need to escape ampersands within URLs. Thus, if you want to link to:

http://images.google.com/images?num=30&q=larry+bird

you need to encode the URL as:

http://images.google.com/images?num=30&amp;q=larry+bird

in your anchor tag href attribute. Needless to say, this is easy to forget, and is probably the single most common source of HTML validation errors in otherwise well-marked-up web sites.

Markdown allows you to use these characters naturally, taking care of all the necessary escaping for you. If you use an ampersand as part of an HTML entity, it remains unchanged; otherwise it will be translated into &amp;.

So, if you want to include a copyright symbol in your article, you can write:

&copy;

and Markdown will leave it alone. But if you write:

AT&T

Markdown will translate it to:

AT&amp;T

Similarly, because Markdown supports inline HTML, if you use angle brackets as delimiters for HTML tags, Markdown will treat them as such. But if you write:

4 < 5

Markdown will translate it to:

4 &lt; 5

However, inside Markdown code spans and blocks, angle brackets and ampersands are always encoded automatically. This makes it easy to use Markdown to write about HTML code. (As opposed to raw HTML, which is a terrible format for writing about HTML syntax, because every single < and & in your example code needs to be escaped.)


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.

Yes, this takes a tad more effort to create a <br />, but a simplistic “every line break is a <br />” rule wouldn’t work for Markdown. Markdown’s email-style blockquoting and multi-paragraph list items work best – and look better – when you format them with hard breaks.

Markdown supports two styles of headers, Setext and atx.

Setext-style headers are “underlined” using equal signs (for first-level headers) and dashes (for second-level headers). For example:

This is an H1
=============

This is an H2
-------------

Any number of underlining =’s or -’s will work.

Atx-style headers use 1–6 hash characters at the start of the line, corresponding to header levels 1–6. For example:

# This is an H1

## This is an H2

###### This is an H6

This is an H1

This is an H2

This is an H6

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.) :

# This is an H1 #

## This is an H2 ##

### This is an H3 ######

Blockquotes

Markdown uses email-style > characters for blockquoting. If you’re familiar with quoting passages of text in an email message, then you know how to create a blockquote in Markdown. It looks best if you hard wrap the text and put a > before every line:

> This is a blockquote 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. Suspendisse
> id sem consectetuer libero luctus adipiscing.

This is a blockquote 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. Suspendisse id sem consectetuer libero luctus adipiscing.

Markdown allows you to be lazy and only put the > before the first line of a hard-wrapped paragraph:

> This is a blockquote 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. Suspendisse
id sem consectetuer libero luctus adipiscing.

Blockquotes can be nested (i.e. a blockquote-in-a-blockquote) by adding additional levels of >:

> This is the first level of quoting.
>
> > This is nested blockquote.
>
> Back to the first level.

This is the first level of quoting.

This is nested blockquote.

Back to the first level.

Blockquotes can contain other Markdown elements, including headers, lists, and code blocks:

> ## This is a header.
>
> 1.   This is the first list item.
> 2.   This is the second list item.
>
> Here's some example code:
>
>     return shell_exec("echo $input | $markdown_script");

This is a header.

  1. This is the first list item.
  2. This is the second list item.

Here’s some example code:

return shell_exec("echo $input | $markdown_script");

Any decent text editor should make email-style quoting easy. For example, with BBEdit, you can make a selection and choose Increase Quote Level from the Text menu.

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
  • 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:

<ol>
<li>Bird</li>
<li>McHale</li>
<li>Parish</li>
</ol>

If you instead wrote the list in Markdown like this:

1.  Bird
1.  McHale
1.  Parish
  1. Bird
  2. McHale
  3. Parish

or even:

3. Bird
1. McHale
8. Parish

you’d get the exact same HTML output. The point is, if you want to, you can use ordinal numbers in your ordered Markdown lists, so that the numbers in your source match the numbers in your published HTML. But if you want to be lazy, you don’t have to.

If you do use lazy list numbering, however, you should still start the list with the number 1. At some point in the future, Markdown may support starting ordered lists at an arbitrary number.

List markers typically start at the left margin, but may be indented by up to three spaces. List markers must be followed by one or more spaces or a tab.

To make lists look nice, you can wrap items with hanging indents:

*   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.
    Suspendisse id sem consectetuer libero luctus adipiscing.
  • 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. Suspendisse id sem consectetuer libero luctus adipiscing.

But if you want to be lazy, you don’t have to:

*   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.
Suspendisse id sem consectetuer libero luctus adipiscing.
  • 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. Suspendisse id sem consectetuer libero luctus adipiscing.

If list items are separated by blank lines, Markdown will wrap the items in <p> tags in the HTML output. For example, this input:

*   Bird
*   Magic

will turn into:

<ul>
<li>Bird</li>
<li>Magic</li>
</ul>
  • Bird
  • Magic

But this:

*   Bird

*   Magic

will turn into:

<ul>
<li><p>Bird</p></li>
<li><p>Magic</p></li>
</ul>
  • Bird

  • Magic

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.

It looks nice if you indent every line of the subsequent paragraphs, but here again, Markdown will allow you to be lazy:

*   This is a list item with two paragraphs.

    This is the second paragraph in the list item. You're
only required to indent the first line. Lorem ipsum dolor
sit amet, consectetuer adipiscing elit.

*   Another item in the same list.

To put a blockquote within a list item, the blockquote’s > delimiters need to be indented:

*   A list item with a blockquote:

    > This is a blockquote
    > inside a list item.

To put a code block within a list item, the code block needs to be indented twice – 8 spaces or two tabs:

*   A list item with a code block:

        <code goes here>

It’s worth noting that it’s possible to trigger an ordered list by accident, by writing something like this:

1986. What a great season.

In other words, a number-period-space sequence at the beginning of a line. To avoid this, you can backslash-escape the period:

1986\. What a great season.

Code Blocks

Pre-formatted code blocks are used for writing about programming or markup source code. Rather than forming normal paragraphs, the lines of a code block are interpreted literally. Markdown wraps a code block in both <pre> and <code> tags.

To produce a code block in Markdown, simply indent every line of the block by at least 4 spaces or 1 tab. For example, given this input:

This is a normal paragraph:

    This is a code block.

Markdown will generate:

<p>This is a normal paragraph:</p>

<pre><code>This is a code block.
</code></pre>

This is a normal paragraph:

This is a code block.

One level of indentation – 4 spaces or 1 tab – is removed from each line of the code block. For example, this:

Here is an example of AppleScript:

    tell application "Foo"
        beep
    end tell

will turn into:

<p>Here is an example of AppleScript:</p>

<pre><code>tell application "Foo"
    beep
end tell
</code></pre>

A code block continues until it reaches a line that is not indented (or the end of the article).

Within a code block, ampersands (&) and angle brackets (< and >) are automatically converted into HTML entities. This makes it very easy to include example HTML source code using Markdown – just paste it and indent it, and Markdown will handle the hassle of encoding the ampersands and angle brackets. For example, this:

    <div class="footer">
        &copy; 2004 Foo Corporation
    </div>

will turn into:

<pre><code>&lt;div class="footer"&gt;
    &amp;copy; 2004 Foo Corporation
&lt;/div&gt;
</code></pre>

Regular Markdown syntax is not processed within code blocks. E.g., asterisks are just literal asterisks within a code block. This means it’s also easy to use Markdown to write about Markdown’s own syntax.

Horizontal Rules

You can produce a horizontal rule tag (<hr />) by placing three or more hyphens, asterisks, or underscores on a line by themselves. If you wish, you may use spaces between the hyphens or asterisks. Each of the following lines will produce a horizontal rule:

* * *

***

*****

- - -

---------------------------------------

Span Elements

Markdown supports two style of links: inline and reference.

In both styles, the link text is delimited by [square brackets].

To create an inline link, use a set of regular parentheses immediately after the link text’s closing square bracket. Inside the parentheses, put the URL where you want the link to point, along with an optional title for the link, surrounded in quotes. For example:

This is [an example](http://example.com/ "Title") inline link.

[This link](http://example.net/) has no title attribute.

Will produce:

<p>This is <a href="http://example.com/" title="Title">
an example</a> inline link.</p>

<p><a href="http://example.net/">This link</a> has no
title attribute.</p>

This is an example inline link.

This link has no title attribute.

If you’re referring to a local resource on the same server, you can use relative paths:

See my [About](/about/) page for details.

Reference-style links use a second set of square brackets, inside which you place a label of your choosing to identify the link:

This is [an example][id] reference-style link.

You can optionally use a space to separate the sets of brackets:

This is [an example] [id] reference-style link.

Then, anywhere in the document, you define your link label like this, on a line by itself:

[id]: http://example.com/  "Optional Title Here"

That is:

  • Square brackets containing the link identifier (optionally indented from the left margin using up to three spaces);
  • followed by a colon;
  • followed by one or more spaces (or tabs);
  • followed by the URL for the link;
  • optionally followed by a title attribute for the link, enclosed in double or single quotes, or enclosed in parentheses.

The following three link definitions are equivalent:

[foo]: http://example.com/  "Optional Title Here"
[foo]: http://example.com/  'Optional Title Here'
[foo]: http://example.com/  (Optional Title Here)

Note: There is a known bug in Markdown.pl 1.0.1 which prevents single quotes from being used to delimit link titles.

The link URL may, optionally, be surrounded by angle brackets:

[id]: <http://example.com/>  "Optional Title Here"

You can put the title attribute on the next line and use extra spaces or tabs for padding, which tends to look better with longer URLs:

[id]: http://example.com/longish/path/to/resource/here
    "Optional Title Here"

Link definitions are only used for creating links during Markdown processing, and are stripped from your document in the HTML output.

Link definition names may consist of letters, numbers, spaces, and punctuation – but they are not case sensitive. E.g. these two links:

[link text][a]
[link text][A]

are equivalent.

The implicit link name shortcut allows you to omit the name of the link, in which case the link text itself is used as the name. Just use an empty set of square brackets – e.g., to link the word “Google” to the google.com web site, you could simply write:

[Google][]

And then define the link:

[Google]: http://google.com/

Because link names may contain spaces, this shortcut even works for multiple words in the link text:

Visit [Daring Fireball][] for more information.

And then define the link:

[Daring Fireball]: http://daringfireball.net/

Link definitions can be placed anywhere in your Markdown document. I tend to put them immediately after each paragraph in which they’re used, but if you want, you can put them all at the end of your document, sort of like footnotes.

Here’s an example of reference links in action:

I get 10 times more traffic from [Google] [1] than from
[Yahoo] [2] or [MSN] [3].

  [1]: http://google.com/        "Google"
  [2]: http://search.yahoo.com/  "Yahoo Search"
  [3]: http://search.msn.com/    "MSN Search"

I get 10 times more traffic from Google than from Yahoo or MSN.

Using the implicit link name shortcut, you could instead write:

I get 10 times more traffic from [Google][] than from
[Yahoo][] or [MSN][].

  [google]: http://google.com/        "Google"
  [yahoo]:  http://search.yahoo.com/  "Yahoo Search"
  [msn]:    http://search.msn.com/    "MSN Search"

Both of the above examples will produce the following HTML output:

<p>I get 10 times more traffic from <a href="http://google.com/"
title="Google">Google</a> than from
<a href="http://search.yahoo.com/" title="Yahoo Search">Yahoo</a>
or <a href="http://search.msn.com/" title="MSN Search">MSN</a>.</p>

For comparison, here is the same paragraph written using Markdown’s inline link style:

I get 10 times more traffic from [Google](http://google.com/ "Google")
than from [Yahoo](http://search.yahoo.com/ "Yahoo Search") or
[MSN](http://search.msn.com/ "MSN Search").

I get 10 times more traffic from Google than from Yahoo or MSN.

The point of reference-style links is not that they’re easier to write. The point is that with reference-style links, your document source is vastly more readable. Compare the above examples: using reference-style links, the paragraph itself is only 81 characters long; with inline-style links, it’s 176 characters; and as raw HTML, it’s 234 characters. In the raw HTML, there’s more markup than there is text.

With Markdown’s reference-style links, a source document much more closely resembles the final output, as rendered in a browser. By allowing you to move the markup-related metadata out of the paragraph, you can add links without interrupting the narrative flow of your prose.

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__

will produce:

<em>single asterisks</em>

<em>single underscores</em>

<strong>double asterisks</strong>

<strong>double underscores</strong>

single asterisks

single underscores

double asterisks

double underscores

You can use whichever style you prefer; the lone restriction is that the same character must be used to open and close an emphasis span.

Emphasis can be used in the middle of a word:

un*frigging*believable

But if you surround an * or _ with spaces, it’ll be treated as a literal asterisk or underscore.

To produce a literal asterisk or underscore at a position where it would otherwise be used as an emphasis delimiter, you can backslash escape it:

\*this text is surrounded by literal asterisks\*

Code

To indicate a span of code, wrap it with backtick quotes (`). Unlike a pre-formatted code block, a code span indicates code within a normal paragraph. For example:

Use the `printf()` function.

will produce:

<p>Use the <code>printf()</code> function.</p>

Use the printf() function.

To include a literal backtick character within a code span, you can use multiple backticks as the opening and closing delimiters:

``There is a literal backtick (`) here.``

which will produce this:

<p><code>There is a literal backtick (`) here.</code></p>

There is a literal backtick (`) here.

The backtick delimiters surrounding a code span may include spaces – one after the opening, one before the closing. This allows you to place literal backtick characters at the beginning or end of a code span:

A single backtick in a code span: `` ` ``

A backtick-delimited string in a code span: `` `foo` ``

will produce:

<p>A single backtick in a code span: <code>`</code></p>

<p>A backtick-delimited string in a code span: <code>`foo`</code></p>

A single backtick in a code span: `

A backtick-delimited string in a code span: `foo`

With a code span, ampersands and angle brackets are encoded as HTML entities automatically, which makes it easy to include example HTML tags. Markdown will turn this:

Please don't use any `<blink>` tags.

into:

<p>Please don't use any <code>&lt;blink&gt;</code> tags.</p>

You can write this:

`&#8212;` is the decimal-encoded equivalent of `&mdash;`.

to produce:

<p><code>&amp;#8212;</code> is the decimal-encoded
equivalent of <code>&amp;mdash;</code>.</p>

Images

Admittedly, it’s fairly difficult to devise a “natural” syntax for placing images into a plain text document format.

Markdown uses an image syntax that is intended to resemble the syntax for links, allowing for two styles: inline and reference.

Inline image syntax looks like this:

![Alt text](/path/to/img.jpg)

![Alt text](/path/to/img.jpg "Optional title")

That is:

  • An exclamation mark: !;
  • followed by a set of square brackets, containing the alt attribute text for the image;
  • followed by a set of parentheses, containing the URL or path to the image, and an optional title attribute enclosed in double or single quotes.

Reference-style image syntax looks like this:

![Alt text][id]

Where “id” is the name of a defined image reference. Image references are defined using syntax identical to link references:

[id]: url/to/image  "Optional title attribute"

As of this writing, Markdown has no syntax for specifying the dimensions of an image; if this is important to you, you can simply use regular HTML <img> tags.


Miscellaneous

Markdown supports a shortcut style for creating “automatic” links for URLs and email addresses: simply surround the URL or email address with angle brackets. What this means is that if you want to show the actual text of a URL or email address, and also have it be a clickable link, you can do this:

<http://example.com/>

Markdown will turn this into:

<a href="http://example.com/">http://example.com/</a>

http://example.com/

Automatic links for email addresses work similarly, except that Markdown will also perform a bit of randomized decimal and hex entity-encoding to help obscure your address from address-harvesting spambots. For example, Markdown will turn this:

<[email protected]>

into something like this:

<a href="&#x6D;&#x61;i&#x6C;&#x74;&#x6F;:&#x61;&#x64;&#x64;&#x72;&#x65;
&#115;&#115;&#64;&#101;&#120;&#x61;&#109;&#x70;&#x6C;e&#x2E;&#99;&#111;
&#109;">&#x61;&#x64;&#x64;&#x72;&#x65;&#115;&#115;&#64;&#101;&#120;&#x61;
&#109;&#x70;&#x6C;e&#x2E;&#99;&#111;&#109;</a>

address@example.com

which will render in a browser as a clickable link to “[email protected]”.

(This sort of entity-encoding trick will indeed fool many, if not most, address-harvesting bots, but it definitely won’t fool all of them. It’s better than nothing, but an address published in this way will probably eventually start receiving spam.)

Backslash Escapes

Markdown allows you to use backslash escapes to generate literal characters which would otherwise have special meaning in Markdown’s formatting syntax. For example, if you wanted to surround a word with literal asterisks (instead of an HTML <em> tag), you can use backslashes before the asterisks, like this:

\*literal asterisks\*

*literal asterisks*

Markdown provides backslash escapes for the following characters:

\   backslash
`   backtick
*   asterisk
_   underscore
{}  curly braces
[]  square brackets
()  parentheses
#   hash mark
+   plus sign
-   minus sign (hyphen)
.   dot
!   exclamation mark

\ backslash ` backtick * asterisk _ underscore {} curly braces [] square brackets () parentheses

hash mark

  • plus sign
  • minus sign (hyphen) . dot ! exclamation mark

MultiMarkdown

Prototype table
Grouping
First Header Second Header Third Header
Content Long Cell
Content Cell Cell
New section More Data
And more And more

Here is some text containing a footnote.[2]

This is a statement that should be attributed to its source[p. 23, 3].

This is a statement that should be attributed to its source[3]

And following is the description of the reference to be used in the bibliography.

Def lists

Apple
Pomaceous fruit of plants of the genus Malus in the family Rosaceae.
An american computer company.
Orange
The fruit of an evergreen tree of the genus Citrus.

Overview

An oft-requested feature was the ability to have Markdown automatically handle withindocument links as easily as it handled external links. To this aim, I added the ability to interpret [Some Text][] as a cross-link, if a header named “Some Text” exists.

As an example, [Metadata][] will take you to the section describing metadata (section 4.1).

Alternatively, you can include an optional label of your choosing to help disambiguate cases where multiple headers have the same title:

This is a formatted ![image][image] and a [link][] with attributes. [image]: http://path.to/image “Image title” width=40px height=400px [link]: http://path.to/link.html “Some Link” class=external style=“border: solid black 1px;”

Images

Backslash Escapes

Markdown allows you to escape special characters that would otherwise be interpreted as Markdown code or HTML with a backslash. For example, if you want to escape


Paragraph with normal text.

Emphasized text, also known as italic.

Strongly emphasized text, also known as bold.

MarkdownExtra tests

From http://michelf.com/projects/php-markdown/extra/


Calepin Style

Paragraphs & Inline Markup

This paragraph contains elements. Up first is the anchor tag, which can occur as an <a> a + href, or an <a> a + name, followed by an ABBR with a title value, followed by an ACRONYM with a title value, followed by a b (for bold) element, followed by a big element, followed by a Citation (cite) element, followed by a Computer code text (code) element, followed by a Deleted (del) element, followed by a Definition term (dfn) element, followed by Emphasized text (em), followed by an italics (i) element.

This next paragraph also contains elements. Up first is the <ins> element, followed by keyboard text (kbd), followed by a <mark> element, followed by a Q element and a double nested Q (a quotation inside a quotation), followed by sample text (samp), followed by a small element, followed by a span element, followed by a strike element, followed by strong text (strong), followed by text in monospace font (tt), followed by an underlined element (u), followed by a Variable element (var, compared to code), all within a containing P. In order to test subscripts and superscripts inside running text, we need constructs like x1 and H2O and Mlle and 1st, and then some mathematical notations: ex, sin2 x, and nested exponents too: ex2 and f(x)g(x)a+b+c (where 2 and a+b+c should appear as exponents of exponents).

h1

h2

h3

h4

h5
h6

Other tricks

Using MathJax

Inline math should come between $ dollars like \(\sum_{k=1}^n k = \frac{n(n+1)}{2}\) and \(\frac{1+\sqrt{5}}{2} = [1; 1, 1, 1, \ldots]\). Perhaps \(A=\{a,b,c\}\) or \(f(x)=x^{3n+1}\) are more your style. \(\forall x \in Y\). \[\int_a^b f(x)\ dx=F(b)-F(a)\]

Display math goes between \\[ and \\] slash-square-brackets, like this: [\sum{k=1}n k = \frac{n(n+1)}{2}] and [ \int{-\infty}{\infty} e{-\frac{x2}{2}} \ dx = \sqrt{2\pi} ]

The code:

Inline math should come between `$` dollars like $\sum_{k=1}^n k = \frac{n(n+1)}{2}$
and  $\frac{1+\sqrt{5}}{2} = [1; 1, 1, 1, \ldots]$. Perhaps $A=\\{a,b,c\\}$
or $f(x)=x^{3n+1}$ are more your style. $\forall x \in Y$. $$\int_a^b f(x)\ dx=F(b)-F(a)$$

Display math goes between `\\[` and `\\]` slash-square-brackets, like this:
\[\sum_{k=1}^n k = \frac{n(n+1)}{2}\]
and
\[
\int_{-\infty}^{\infty} e^{-\frac{x^2}{2}} \ dx = \sqrt{2\pi}
\]

To get MathJax to display, place the following in your Markdown or reStructuredText source:

#!javascript
<style type="text/css">
    .math span {
        color: inherit;
    }
</style>

<script language="javascript">
    if(window.MathJax===undefined){
        var script = document.createElement("script");
        script.type = "text/javascript";
        script.src = "http://cdn.mathjax.org/mathjax/latest/MathJax.js";
        var config = 'MathJax.Hub.Config({' +
                    'extensions: ["tex2jax.js","TeX/AMSmath.js","TeX/AMSsymbols.js"],' +
                    'tex2jax: { '+
                      'inlineMath: [ ["$","$"]], '+
                      'displayMath: [["\\[","\\]"]],'+
                      'processEscapes: true '+
                    '},' +
                    'jax: ["input/TeX","output/HTML-CSS"]' +
                    '});' +
                    'MathJax.Hub.Startup.onload();';
        if (window.opera)
            script.innerHTML = config;
        else
            script.text = config;
        document.getElementsByTagName("head")[0].appendChild(script);
    }
</script>

Note: based on Christian Perfect’s code from http://christianperfect.calepin.co/mathjax-test.html and http://christianperfect.calepin.co/a-second-post.html.


Markdown

Note: This document is itself written using Markdown; you can see the source for it by adding ‘.text’ to the URL.


Overview

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, atx, Textile, reStructuredText, Grutatext, and EtText – the single biggest source of inspiration for Markdown’s syntax is the format of plain text email.

To this end, Markdown’s syntax is comprised entirely of punctuation characters, which punctuation characters have been carefully chosen so as to look like what they mean. E.g., asterisks around a word actually look like *emphasis*. Markdown lists look like, well, lists. Even blockquotes look like quoted passages of text, assuming you’ve ever used email.

Inline HTML

Markdown’s syntax is intended for one purpose: to be used as a format for writing for the web.

Markdown is not a replacement for HTML, or even close to it. Its syntax is very small, corresponding only to a very small subset of HTML tags. The idea is not to create a syntax that makes it easier to insert HTML tags. In my opinion, HTML tags are already easy to insert. The idea for Markdown is to make it easy to read, write, and edit prose. HTML is a publishing format; Markdown is a writing format. Thus, Markdown’s formatting syntax only addresses issues that can be conveyed in plain text.

For any markup that is not covered by Markdown’s syntax, you simply use HTML itself. There’s no need to preface it or delimit it to indicate that you’re switching from Markdown to HTML; you just use the tags.

The only restrictions are that block-level HTML elements – e.g. <div>, <table>, <pre>, <p>, etc. – must be separated from surrounding content by blank lines, and the start and end tags of the block should not be indented with tabs or spaces. Markdown is smart enough not to add extra (unwanted) <p> tags around HTML block-level tags.

For example, to add an HTML table to a Markdown article:

This is a regular paragraph.

<table>
    <tr>
        <td>Foo</td>
    </tr>
</table>

This is another regular paragraph.

Note that Markdown formatting syntax is not processed within block-level HTML tags. E.g., you can’t use Markdown-style *emphasis* inside an HTML block.

Span-level HTML tags – e.g. <span>, <cite>, or <del> – can be used anywhere in a Markdown paragraph, list item, or header. If you want, you can even use HTML tags instead of Markdown formatting; e.g. if you’d prefer to use HTML <a> or <img> tags instead of Markdown’s link or image syntax, go right ahead.

Unlike block-level HTML tags, Markdown syntax is processed within span-level tags.

Automatic Escaping for Special Characters

In HTML, there are two characters that demand special treatment: < and &. Left angle brackets are used to start tags; ampersands are used to denote HTML entities. If you want to use them as literal characters, you must escape them as entities, e.g. &lt;, and &amp;.

Ampersands in particular are bedeviling for web writers. If you want to write about ‘AT&T’, you need to write ‘AT&amp;T’. You even need to escape ampersands within URLs. Thus, if you want to link to:

http://images.google.com/images?num=30&q=larry+bird

you need to encode the URL as:

http://images.google.com/images?num=30&amp;q=larry+bird

in your anchor tag href attribute. Needless to say, this is easy to forget, and is probably the single most common source of HTML validation errors in otherwise well-marked-up web sites.

Markdown allows you to use these characters naturally, taking care of all the necessary escaping for you. If you use an ampersand as part of an HTML entity, it remains unchanged; otherwise it will be translated into &amp;.

So, if you want to include a copyright symbol in your article, you can write:

&copy;

and Markdown will leave it alone. But if you write:

AT&T

Markdown will translate it to:

AT&amp;T

Similarly, because Markdown supports inline HTML, if you use angle brackets as delimiters for HTML tags, Markdown will treat them as such. But if you write:

4 < 5

Markdown will translate it to:

4 &lt; 5

However, inside Markdown code spans and blocks, angle brackets and ampersands are always encoded automatically. This makes it easy to use Markdown to write about HTML code. (As opposed to raw HTML, which is a terrible format for writing about HTML syntax, because every single < and & in your example code needs to be escaped.)


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.

Yes, this takes a tad more effort to create a <br />, but a simplistic “every line break is a <br />” rule wouldn’t work for Markdown. Markdown’s email-style blockquoting and multi-paragraph list items work best – and look better – when you format them with hard breaks.

Markdown supports two styles of headers, Setext and atx.

Setext-style headers are “underlined” using equal signs (for first-level headers) and dashes (for second-level headers). For example:

This is an H1
=============

This is an H2
-------------

Any number of underlining =’s or -’s will work.

Atx-style headers use 1–6 hash characters at the start of the line, corresponding to header levels 1–6. For example:

# This is an H1

## This is an H2

###### This is an H6

This is an H1

This is an H2

This is an H6

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.) :

# This is an H1 #

## This is an H2 ##

### This is an H3 ######

Blockquotes

Markdown uses email-style > characters for blockquoting. If you’re familiar with quoting passages of text in an email message, then you know how to create a blockquote in Markdown. It looks best if you hard wrap the text and put a > before every line:

> This is a blockquote 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. Suspendisse
> id sem consectetuer libero luctus adipiscing.

This is a blockquote 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. Suspendisse id sem consectetuer libero luctus adipiscing.

Markdown allows you to be lazy and only put the > before the first line of a hard-wrapped paragraph:

> This is a blockquote 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. Suspendisse
id sem consectetuer libero luctus adipiscing.

Blockquotes can be nested (i.e. a blockquote-in-a-blockquote) by adding additional levels of >:

> This is the first level of quoting.
>
> > This is nested blockquote.
>
> Back to the first level.

This is the first level of quoting.

This is nested blockquote.

Back to the first level.

Blockquotes can contain other Markdown elements, including headers, lists, and code blocks:

> ## This is a header.
>
> 1.   This is the first list item.
> 2.   This is the second list item.
>
> Here's some example code:
>
>     return shell_exec("echo $input | $markdown_script");

This is a header.

  1. This is the first list item.
  2. This is the second list item.

Here’s some example code:

return shell_exec("echo $input | $markdown_script");

Any decent text editor should make email-style quoting easy. For example, with BBEdit, you can make a selection and choose Increase Quote Level from the Text menu.

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
  • 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:

<ol>
<li>Bird</li>
<li>McHale</li>
<li>Parish</li>
</ol>

If you instead wrote the list in Markdown like this:

1.  Bird
1.  McHale
1.  Parish
  1. Bird
  2. McHale
  3. Parish

or even:

3. Bird
1. McHale
8. Parish

you’d get the exact same HTML output. The point is, if you want to, you can use ordinal numbers in your ordered Markdown lists, so that the numbers in your source match the numbers in your published HTML. But if you want to be lazy, you don’t have to.

If you do use lazy list numbering, however, you should still start the list with the number 1. At some point in the future, Markdown may support starting ordered lists at an arbitrary number.

List markers typically start at the left margin, but may be indented by up to three spaces. List markers must be followed by one or more spaces or a tab.

To make lists look nice, you can wrap items with hanging indents:

*   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.
    Suspendisse id sem consectetuer libero luctus adipiscing.
  • 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. Suspendisse id sem consectetuer libero luctus adipiscing.

But if you want to be lazy, you don’t have to:

*   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.
Suspendisse id sem consectetuer libero luctus adipiscing.
  • 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. Suspendisse id sem consectetuer libero luctus adipiscing.

If list items are separated by blank lines, Markdown will wrap the items in <p> tags in the HTML output. For example, this input:

*   Bird
*   Magic

will turn into:

<ul>
<li>Bird</li>
<li>Magic</li>
</ul>
  • Bird
  • Magic

But this:

*   Bird

*   Magic

will turn into:

<ul>
<li><p>Bird</p></li>
<li><p>Magic</p></li>
</ul>
  • Bird

  • Magic

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.

It looks nice if you indent every line of the subsequent paragraphs, but here again, Markdown will allow you to be lazy:

*   This is a list item with two paragraphs.

    This is the second paragraph in the list item. You're
only required to indent the first line. Lorem ipsum dolor
sit amet, consectetuer adipiscing elit.

*   Another item in the same list.

To put a blockquote within a list item, the blockquote’s > delimiters need to be indented:

*   A list item with a blockquote:

    > This is a blockquote
    > inside a list item.

To put a code block within a list item, the code block needs to be indented twice – 8 spaces or two tabs:

*   A list item with a code block:

        <code goes here>

It’s worth noting that it’s possible to trigger an ordered list by accident, by writing something like this:

1986. What a great season.

In other words, a number-period-space sequence at the beginning of a line. To avoid this, you can backslash-escape the period:

1986\. What a great season.

Code Blocks

Pre-formatted code blocks are used for writing about programming or markup source code. Rather than forming normal paragraphs, the lines of a code block are interpreted literally. Markdown wraps a code block in both <pre> and <code> tags.

To produce a code block in Markdown, simply indent every line of the block by at least 4 spaces or 1 tab. For example, given this input:

This is a normal paragraph:

    This is a code block.

Markdown will generate:

<p>This is a normal paragraph:</p>

<pre><code>This is a code block.
</code></pre>

This is a normal paragraph:

This is a code block.

One level of indentation – 4 spaces or 1 tab – is removed from each line of the code block. For example, this:

Here is an example of AppleScript:

    tell application "Foo"
        beep
    end tell

will turn into:

<p>Here is an example of AppleScript:</p>

<pre><code>tell application "Foo"
    beep
end tell
</code></pre>

A code block continues until it reaches a line that is not indented (or the end of the article).

Within a code block, ampersands (&) and angle brackets (< and >) are automatically converted into HTML entities. This makes it very easy to include example HTML source code using Markdown – just paste it and indent it, and Markdown will handle the hassle of encoding the ampersands and angle brackets. For example, this:

    <div class="footer">
        &copy; 2004 Foo Corporation
    </div>

will turn into:

<pre><code>&lt;div class="footer"&gt;
    &amp;copy; 2004 Foo Corporation
&lt;/div&gt;
</code></pre>

Regular Markdown syntax is not processed within code blocks. E.g., asterisks are just literal asterisks within a code block. This means it’s also easy to use Markdown to write about Markdown’s own syntax.

Span Elements

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__

will produce:

<em>single asterisks</em>

<em>single underscores</em>

<strong>double asterisks</strong>

<strong>double underscores</strong>

single asterisks

single underscores

double asterisks

double underscores

You can use whichever style you prefer; the lone restriction is that the same character must be used to open and close an emphasis span.

Emphasis can be used in the middle of a word:

un*frigging*believable

But if you surround an * or _ with spaces, it’ll be treated as a literal asterisk or underscore.

To produce a literal asterisk or underscore at a position where it would otherwise be used as an emphasis delimiter, you can backslash escape it:

\*this text is surrounded by literal asterisks\*

Code

To indicate a span of code, wrap it with backtick quotes (`). Unlike a pre-formatted code block, a code span indicates code within a normal paragraph. For example:

Use the `printf()` function.

will produce:

<p>Use the <code>printf()</code> function.</p>

Use the printf() function.

To include a literal backtick character within a code span, you can use multiple backticks as the opening and closing delimiters:

``There is a literal backtick (`) here.``

which will produce this:

<p><code>There is a literal backtick (`) here.</code></p>

There is a literal backtick (`) here.

The backtick delimiters surrounding a code span may include spaces – one after the opening, one before the closing. This allows you to place literal backtick characters at the beginning or end of a code span:

A single backtick in a code span: `` ` ``

A backtick-delimited string in a code span: `` `foo` ``

will produce:

<p>A single backtick in a code span: <code>`</code></p>

<p>A backtick-delimited string in a code span: <code>`foo`</code></p>

A single backtick in a code span: `

A backtick-delimited string in a code span: `foo`

With a code span, ampersands and angle brackets are encoded as HTML entities automatically, which makes it easy to include example HTML tags. Markdown will turn this:

Please don't use any `<blink>` tags.

into:

<p>Please don't use any <code>&lt;blink&gt;</code> tags.</p>

You can write this:

`&#8212;` is the decimal-encoded equivalent of `&mdash;`.

to produce:

<p><code>&amp;#8212;</code> is the decimal-encoded
equivalent of <code>&amp;mdash;</code>.</p>

Images

Admittedly, it’s fairly difficult to devise a “natural” syntax for placing images into a plain text document format.

Markdown uses an image syntax that is intended to resemble the syntax for links, allowing for two styles: inline and reference.

Inline image syntax looks like this:

![Alt text](/path/to/img.jpg)

![Alt text](/path/to/img.jpg "Optional title")

That is:

  • An exclamation mark: !;
  • followed by a set of square brackets, containing the alt attribute text for the image;
  • followed by a set of parentheses, containing the URL or path to the image, and an optional title attribute enclosed in double or single quotes.

Reference-style image syntax looks like this:

![Alt text][id]

Where “id” is the name of a defined image reference. Image references are defined using syntax identical to link references:

[id]: url/to/image  "Optional title attribute"

As of this writing, Markdown has no syntax for specifying the dimensions of an image; if this is important to you, you can simply use regular HTML <img> tags.


Backslash Escapes

Markdown allows you to use backslash escapes to generate literal characters which would otherwise have special meaning in Markdown’s formatting syntax. For example, if you wanted to surround a word with literal asterisks (instead of an HTML <em> tag), you can use backslashes before the asterisks, like this:

\*literal asterisks\*

*literal asterisks*

Markdown provides backslash escapes for the following characters:

\   backslash
`   backtick
*   asterisk
_   underscore
{}  curly braces
[]  square brackets
()  parentheses
#   hash mark
+   plus sign
-   minus sign (hyphen)
.   dot
!   exclamation mark

\ backslash ` backtick * asterisk _ underscore {} curly braces [] square brackets () parentheses

hash mark

  • plus sign
  • minus sign (hyphen) . dot ! exclamation mark

MultiMarkdown

Prototype table
Grouping
First Header Second Header Third Header
Content Long Cell
Content Cell Cell
New section More Data
And more And more

Here is some text containing a footnote.[2]

This is a statement that should be attributed to its source[p. 23, 3].

This is a statement that should be attributed to its source[3]

And following is the description of the reference to be used in the bibliography.

Preformatted Code Blocks

Indent every line of a code block by at least 4 spaces or 1 tab.

This is a normal paragraph.

    This is a preformatted
    code block.

Horizontal Rules

Three or more dashes or asterisks:

---

* * *

- - - -

Manual Line Breaks

End a line with two or more spaces:

Roses are red,
Violets are blue.

Roses are red, Violets are blue.


  1. And that’s the footnote.  ↩

  2. Here is the text of the footnote itself.  ↩

  3. John Doe. Some Big Fancy Book. Vanity Press, 2006.