MARKDOWN(7)            Miscellaneous Information Manual            MARKDOWN(7)

NAME
     Markdown - The Markdown text formatting syntax

DESCRIPTION
   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" Dtext 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.

   Headers
     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

     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.

     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.

     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");

     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

     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

     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.

     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.

     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>

     But this:

               *   Bird

               *   Magic

     will turn into:

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

     List items may consist of multiple paragraphs. Each subsequent paragraph
     in a list item must be intended 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>

     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
   Links
     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>

     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:

     o   Square brackets containing the link identifier (optionally indented
         from the left margin using up to three spaces);

     o   followed by a colon;

     o   followed by one or more spaces (or tabs);

     o   followed by the URL for the link;

     o   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 constist 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"

     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").

     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>

     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*fucking*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>

     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>

     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>

     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 size "Optional title")

     That is:

     o   An exclamation mark: `!`;

     o   followed by a set of square brackets, containing the `alt` attribute
         text for the image;

     o   followed by a set of parentheses, containing the URL or path to the
         image, an optional `size` attribute (in width c height format)
         prefixed with a `=`, 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 size "Optional title attribute"

Miscellaneous
   Automatic Links
     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>

     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:

               <address@example.com>

     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>

     which will render in a browser as a clickable link to
     "address@example.com".

     (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 add backslashes
     before the asterisks, like this:

               \*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

BUGS
     Markdown assumes that tabs are set to 4 spaces.

AUTHOR
     John Gruber http://daringfireball.net/

SEE ALSO
     markdown(1), markdown(3), mkd-callbacks(3), mkd-functions(3),
     mkd-extensions(7).

     http://daringfireball.net/projects/markdown
     http://docutils.sourceforge.net/mirror/setext.html
     http://www.aaronsw.com/2002/atx/
     http://textism.com/tools/textile/
     http://docutils.sourceforge.net/rst.html
     http://www.triptico.com/software/grutatxt.html
     http://ettext.taint.org/doc/

MASTODON                       December 22, 2007                      MASTODON