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markdown.6.txt
MARKDOWN(6) MARKDOWN(6)
NAME
Markdown - text formatting syntax
DESCRIPTION
Markdown is a text markup syntax for machine conversion to
the more complex HTML or XHTML markup languages. It is
intended to be easy to read and to write, with emphasis on
readability. A Markdown-formatted document should be pub-
lishable as-is, in plain text, without the formatting dis-
tracting the reader.
The biggest source of inspiration for Markdown's syntax is
the format of plain text email. The markup is comprised
entirely of punctuation characters, chosen so as to look
like what they mean. Asterisks around a word look like
*emphasis*. Markdown lists look like lists. Even block-
quotes look like quoted passages of text, assuming the
reader has used email.
Block Elements
Paragraphs and Line Breaks
A paragraph is 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 contain-
ing nothing but spaces or tabs is considered blank.) Nor-
mal paragraphs should not be indented with spaces or
tabs.
Lines may be freely broken for readability; Markdown does
not translate source line breaks to <br /> tags. To
request generation of <br /> in the output, end a line
with two or more spaces, then a newline.
Headings
Headings can be marked in two ways, called setext and
atx.
Setext-style headings are ``underlined'' using equal
signs (for first-level headings) and dashes (for second-
level headings).
Atx-style headings use 1-6 hash characters at the start
of the line, corresponding to HTML <h^(1-6)^>. Optional
closing hashes may follow the heading text.
Blockquotes
Lines beginning with > are output in blockquotes. Block-
quotes can be nested by multiple levels of >>. Block-
quotes can contain other Markdown elements, including
headings, lists, and code blocks.
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MARKDOWN(6) MARKDOWN(6)
Lists
Markdown supports ordered (numbered) and unordered (bul-
leted) lists. 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,
then the list item text. A newline terminates each list
item.
Unordered lists use asterisks, pluses, and hyphens inter-
changeably as list markers.
Ordered lists use integers followed by periods as list
markers. The order of the integers is not interpreted,
but the list should begin with 1.
If list items are separated by blank lines, Markdown will
wrap each list item in <p> tags in the HTML output.
List items may consist of multiple paragraphs. Each sub-
sequent paragraph within a list item must be indented by
either 4 spaces or one tab. To put a blockquote within a
list item, the blockquote's > marker needs to be
indented. To put a code block within a list item, the
code block needs to be indented twice -- 8 spaces or two
tabs.
Code Blocks
To produce a code block, indent every line of the block
by at least 4 spaces or 1 tab. A code block continues
until it reaches a line that is not indented.
Rather than forming normal paragraphs, the lines of a
code block are interpreted literally. Regular Markdown
syntax is not processed within code blocks. Markdown
wraps a code block in both <pre> and <code> tags. One
level of indentation -- 4 spaces or 1 tab -- is removed
from each line of the code block in the output.
Horizontal Rules
Produce a horizontal rule tag (<hr />) by placing three
or more hyphens, asterisks, or underscores on a line by
themselves.
Span Elements
Links
Markdown supports two styles 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 link URL, along with an optional title for the
link surrounded in double quotes. For example:
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MARKDOWN(6) MARKDOWN(6)
An [example](http://example.com/ "Title") inline link.
Reference-style links use a second set of square brack-
ets, inside which you place a label of your choosing to
identify the link:
An [example][id] reference-style link.
The label is then assigned a value on its own line, any-
where in the document:
[id]: http://example.com/ "Optional Title"
Link label names may consist of letters, numbers, spaces,
and punctuation. Labels are not case sensitive. An
empty label bracket set after a reference-style link
implies the link label is equivalent to the link text. A
URL value can then be assigned to the link by referencing
the link text as the label name.
Emphasis
Markdown treats asterisks (*) and underscores (_) as
indicators of emphasis. Text surrounded with single
asterisks or underscores will be wrapped with an HTML
<em> tag. Double asterisks or underscores generate an
HTML <strong> tag.
Code
To indicate a span of code, wrap it with backtick quotes
(`). Unlike a code block, a code span indicates code
within a normal paragraph. To include a literal backtick
character within a code span, you can use multiple back-
ticks as the opening and closing delimiters:
``There is a literal backtick (`) here.``
Images
Markdown image syntax is intended to resemble that for
links, allowing for two styles, once again inline and
reference. The syntax is as for each respective style of
link, described above, but prefixed with an exclamation
mark character (!). Inline image syntax looks like this:
![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:
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MARKDOWN(6) MARKDOWN(6)
![Alt text][id]
Where id is a label used as for reference-style URL
links, described above.
Convenience
Automatic Links
There is a shortcut style for creating ``automatic''
links for URLs and email addresses. Surround the URL or
address with angle brackets.
Backslash Escapes
Use backslash escapes to generate literal characters
which would otherwise have special meaning in Markdown's
formatting syntax.
Inline HTML
For markup that is not covered by Markdown's syntax, sim-
ply use the HTML directly. The only restrictions are
that block-level HTML elements -- <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 for-
matting syntax is not processed within block-level HTML
tags.
Span-level HTML tags -- e.g. <span>, <cite>, or <del> --
can be used anywhere in a Markdown paragraph, list item,
or heading. It is permitted to use HTML tags instead of
Markdown formatting; e.g. HTML <a> or <img> tags instead
of Markdown's link or image syntax. Unlike block-level
HTML tags, Markdown syntax is processed within the ele-
ments of span-level tags.
Automatic Special Character Escapes
To be displayed literally in a user agent, the characters
< and & must appear as escaped entities in HTML source,
e.g. &lt; and &amp;. Markdown allows natural use of
these characters, taking care of the necessary escaping.
The ampersand part of a directly-used HTML entity remains
unchanged; otherwise it will be translated into &amp;.
Inside code spans and blocks, angle brackets and amper-
sands are always encoded automatically. This makes it
easy to use Markdown to write about HTML code.
Smarty Pants
The markdown(1) utility transforms a few plain text symbols
into their typographically-fancier HTML entity equivalents.
These are extensions to the standard Markdown syntax.
Punctuation
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MARKDOWN(6) MARKDOWN(6)
Input single- and double-quotes are transformed into
``curly'' quote entities in the output (e.g., 'text'
becomes &lsquo;text&rsquo;). Input double-dashes (--)
and triple-dashes become en- and em-dashes, respectively,
while a series of three dots (...) in the input becomes
an ellipsis entity (&hellip;) in the HTML output.
Symbols
Three other transformations replace the common plain-text
shorthands (c), (r), and (tm) from the input with their
respective HTML entities. (As in (c) becoming &copy;, the
Copyright symbol entity.)
Fractions
A small set of plain-text shorthands for fractions is
recognized. 1/4 becomes &frac14;, for example. These
fraction notations are replaced with their HTML entity
equivalents: 1/4, 1/2, 3/4. 1/4th and 3/4ths are
replaced with their entity and the indicated ordinal suf-
fix letters.
Like the basic Markdown syntax, none of the ``Smarty Pants''
extensions are processed inside code blocks or spans.
Discount Extensions
Markdown(1) recognizes some extensions to the Markdown for-
mat, many of them adopted or adapted from other Markdown
interpreters or document formatting systems.
Pandoc Headers
If markdown was configured with --enable-pandoc-header,
the markdown source can have a 3-line Pandoc header in
the format of
% Title
% Author
% Date
whose data is available to the mkd_doc_title,
mkd_doc_author, and mkd_doc_date (in markdown(2)) func-
tions.
Embedded Stylesheets
Stylesheets may be defined and modified in a <style>
block. A style block is parsed like any other block-
level HTML; <style> starting on column 1, raw HTML (or,
in this case, CSS ) following it, and either ending with
a </style> at the end of the line or at the beginning of
a subsequent line.
Style blocks apply to the entire document regardless of
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MARKDOWN(6) MARKDOWN(6)
where they are defined.
Image Dimensions
Image specification has been extended with an argument
describing image dimensions: =heightxwidth. For an image
400 pixels high and 300 wide, the new syntax is:
![Alt text](/path/to/image.jpg =400x300 "Title")
Pseudo-Protocols
Pseudo-protocols that may replace the common http: or
mailto: have been added to the link syntax described
above.
abbr: Text following is used as the title attribute of an
abbr tag wrapping the link text. So [LT](abbr:Link Text)
gives <abbr title="Link Text">LT</abbr>.
id: The link text is marked up and written to the output,
wrapped with <a id=text following> and </a>.
class:
The link text is marked up and written to the output,
wrapped with <span class=text following> and </span>.
raw: Text following is written to the output with no fur-
ther processing. The link text is discarded.
Alphabetic Lists
If markdown was configured with --enable-alpha-list,
a. this
b. is
c. an alphabetic
d. list
yields an HTML ol ordered list.
Definition Lists
If configured with --enable-dl-tag, markup for definition
lists is enabled. A definition list item is defined as
=term=
definition
Tables
Tables are specified with a pipe (|) and dash (-) mark-
ing. The markdown text
header0|header1
-------|-------
textA|textB
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MARKDOWN(6) MARKDOWN(6)
textC|textD
will produce an HTML table of two columns and three rows.
A header row is designated by ``underlining'' with
dashes. Declare a column's alignment by affixing a colon
(:) to the left or right end of the dashes underlining
its header. In the output, this yields the corresponding
value for the align attribute on each td cell in the col-
umn. A colon at both ends of a column's header dashes
indicates center alignment.
Relaxed Emphasis
The rules for emphasis are changed so that a single _
will not count as an emphasis character in the middle of
a word. This is useful for documenting some code where _
appears frequently, and would normally require a back-
slash escape.
SEE ALSO
markdown(1), markdown(2)
http://daringfireball.net/projects/markdown/syntax/, ``Mark-
down: Syntax''.
http://daringfireball.net/projects/smartypants/, ``Smarty
Pants''.
http://michelf.com/projects/php-markdown/extra/#table, ``PHP
Markdown Extra: Tables''.
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