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- .\"
- .Dd Dec 22, 2007
- .Dt MARKDOWN 7
- .Os MASTODON
- .Sh NAME
- .Nm Markdown
- .Nd The Markdown text formatting syntax
- .Sh DESCRIPTION
- .Ss Philosophy
- .Nm Markdown
- is intended to be as easy-to-read and easy-to-write as is feasible.
- .Pp
- 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
- .Em Setext ,
- .Em atx ,
- .Em Textile ,
- .Em reStructuredText ,
- .Em Grutatext ,
- and
- .Em EtText
- \-\- the single biggest source of
- inspiration for
- Markdown's
- syntax is the format of plain text email.
- .Pp
- 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.
- .Ss Inline HTML
- Markdown's syntax is intended for one purpose: to be used as a
- format for
- .Em writing
- for the web.
- .Pp
- .Nm
- 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
- .Em 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
- .Em publishing
- format; Markdown is a
- .Em writing
- format. Thus, Markdown's formatting syntax only addresses issues that
- can be conveyed in plain text.
- .Pp
- 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.
- .Pp
- The only restrictions are that block-level HTML elements -- e.g.
- .Li \<div> ,
- .Li \<table> ,
- .Li \<pre> ,
- .Li \<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)
- .Li \<p>
- tags around HTML block-level tags.
- .Pp
- For example, to add an HTML table to a Markdown article:
- .Bd -literal -offset indent
- This is a regular paragraph.
-
- <table>
- <tr>
- <td>Foo</td>
- </tr>
- </table>
-
- This is another regular paragraph.
- .Ed
- .Pp
- Note that Markdown formatting syntax is not processed within block-level
- HTML tags. E.g., you can't use Markdown-style
- .Li *emphasis*
- inside an HTML block.
- .Pp
- Span-level HTML tags -- e.g.
- .Li \<span> ,
- .Li \<cite> ,
- or
- .Li \<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
- .Li \<a>
- or
- .Li \<img>
- tags instead of Markdown's
- link or image syntax, go right ahead.
- .Pp
- Unlike block-level HTML tags, Markdown syntax *is* processed within
- span-level tags.
- .Ss 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. `<`, and
- `&`.
- .Pp
- Ampersands in particular are bedeviling for web writers. If you want to
- write about 'AT&T', you need to write '`AT&T`'. You even need to
- escape ampersands within URLs. Thus, if you want to link to:
- .Bd -literal -offset indent
- http://images.google.com/images?num=30&q=larry+bird
- .Ed
- .Pp
- you need to encode the URL as:
- .Bd -literal -offset indent
- http://images.google.com/images?num=30&q=larry+bird
- .Ed
- .Pp
- 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.
- .Pp
- .Nm
- 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 `&`.
- .Pp
- So, if you want to include a copyright symbol in your article, you can write:
- .Bd -literal -offset indent
- ©
- .Ed
- .Pp
- and Markdown will leave it alone. But if you write:
- .Bd -literal -offset indent
- AT&T
- .Ed
- .Pp
- .Nm
- will translate it to:
- .Bd -literal -offset indent
- AT&T
- .Ed
- .Pp
- 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:
- .Bd -literal -offset indent
- 4 < 5
- .Ed
- .Pp
- .Nm
- will translate it to:
- .Bd -literal -offset indent
- 4 < 5
- .Ed
- .Pp
- 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.)
- .Sh Block Elements
- .Ss Paragraphs and Line Breaks
- .Pp
- 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.
- .Pp
- The implication of the
- .Qq one or more consecutive lines of text
- rule is
- that Markdown supports
- .Qq hard-wrapped
- Dtext paragraphs. This differs
- significantly from most other text-to-HTML formatters (including Movable
- Type's
- .Qq Convert Line Breaks
- option) which translate every line break
- character in a paragraph into a `<br />` tag.
- .Pp
- When you *do* want to insert a `<br />` break tag using Markdown, you
- end a line with two or more spaces, then type return.
- .Pp
- 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
- .Sx blockquoting
- and multi-paragraph
- .Sx list items
- work best -- and look better -- when you format them with hard breaks.
- .Ss Headers
- .Nm
- supports two styles of headers,
- .Em Setext
- and
- .Em atx .
- .Pp
- Setext-style headers are
- .Sq underlined
- using equal signs (for first-level
- headers) and dashes (for second-level headers). For example:
- .Bd -literal -offset indent
- This is an H1
- =============
-
- This is an H2
- -------------
- .Ed
- .Pp
- Any number of underlining `=`'s or `-`'s will work.
- .Pp
- Atx-style headers use 1-6 hash characters at the start of the line,
- corresponding to header levels 1-6. For example:
- .Bd -literal -offset indent
- # This is an H1
-
- ## This is an H2
-
- ###### This is an H6
- .Ed
- .Pp
- Optionally, you may
- .Qq 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.) :
- .Bd -literal -offset indent
- # This is an H1 #
-
- ## This is an H2 ##
-
- ### This is an H3 ######
- .Ed
- .Pp
- .Ss Blockquotes
- .Nm
- 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:
- .Bd -literal -offset indent
- > 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.
- .Ed
- .Pp
- .Nm
- allows you to be lazy and only put the `>` before the first
- line of a hard-wrapped paragraph:
- .Bd -literal -offset indent
- > 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.
- .Ed
- .Pp
- Blockquotes can be nested (i.e. a blockquote-in-a-blockquote) by
- adding additional levels of `>`:
- .Bd -literal -offset indent
- > This is the first level of quoting.
- >
- > > This is nested blockquote.
- >
- > Back to the first level.
- .Ed
- .Pp
- Blockquotes can contain other Markdown elements, including headers, lists,
- and code blocks:
- .Bd -literal -offset indent
- > ## 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");
- .Ed
- .Pp
- 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.
- .Ss Lists
- .Nm
- supports ordered (numbered) and unordered (bulleted) lists.
- .Pp
- Unordered lists use asterisks, pluses, and hyphens -- interchangably
- \-- as list markers:
- .Bd -literal -offset indent
- * Red
- * Green
- * Blue
- .Ed
- .Pp
- is equivalent to:
- .Bd -literal -offset indent
- + Red
- + Green
- + Blue
- .Ed
- .Pp
- and:
- .Bd -literal -offset indent
- - Red
- - Green
- - Blue
- .Ed
- .Pp
- Ordered lists use numbers followed by periods:
- .Bd -literal -offset indent
- 1. Bird
- 2. McHale
- 3. Parish
- .Ed
- .Pp
- 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:
- .Bd -literal -offset indent
- <ol>
- <li>Bird</li>
- <li>McHale</li>
- <li>Parish</li>
- </ol>
- .Ed
- .Pp
- If you instead wrote the list in Markdown like this:
- .Bd -literal -offset indent
- 1. Bird
- 1. McHale
- 1. Parish
- .Ed
- .Pp
- or even:
- .Bd -literal -offset indent
- 3. Bird
- 1. McHale
- 8. Parish
- .Ed
- .Pp
- 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.
- .Pp
- 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.
- .Pp
- 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.
- .Pp
- To make lists look nice, you can wrap items with hanging indents:
- .Bd -literal -offset indent
- * 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.
- .Ed
- .Pp
- But if you want to be lazy, you don't have to:
- .Bd -literal -offset indent
- * 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.
- .Ed
- .Pp
- If list items are separated by blank lines, Markdown will wrap the
- items in `<p>` tags in the HTML output. For example, this input:
- .Bd -literal -offset indent
- * Bird
- * Magic
- .Ed
- .Pp
- will turn into:
- .Bd -literal -offset indent
- <ul>
- <li>Bird</li>
- <li>Magic</li>
- </ul>
- .Ed
- .Pp
- But this:
- .Bd -literal -offset indent
- * Bird
-
- * Magic
- .Ed
- .Pp
- will turn into:
- .Bd -literal -offset indent
- <ul>
- <li><p>Bird</p></li>
- <li><p>Magic</p></li>
- </ul>
- .Ed
- .Pp
- List items may consist of multiple paragraphs. Each subsequent
- paragraph in a list item must be intended by either 4 spaces
- or one tab:
- .Bd -literal -offset indent
- 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.
- .Ed
- .Pp
- It looks nice if you indent every line of the subsequent
- paragraphs, but here again, Markdown will allow you to be
- lazy:
- .Bd -literal -offset indent
- * 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.
- .Ed
- .Pp
- To put a blockquote within a list item, the blockquote's `>`
- delimiters need to be indented:
- .Bd -literal -offset indent
- * A list item with a blockquote:
-
- > This is a blockquote
- > inside a list item.
- .Ed
- .Pp
- To put a code block within a list item, the code block needs
- to be indented *twice* -- 8 spaces or two tabs:
- .Bd -literal -offset indent
- * A list item with a code block:
-
- <code goes here>
- .Ed
- .Pp
- It's worth noting that it's possible to trigger an ordered list by
- accident, by writing something like this:
- .Bd -literal -offset indent
- 1986. What a great season.
- .Ed
- .Pp
- In other words, a *number-period-space* sequence at the beginning of a
- line. To avoid this, you can backslash-escape the period:
- .Bd -literal -offset indent
- 1986\\. What a great season.
- .Ed
- .Pp
- .Ss 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.
- .Pp
- 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:
- .Bd -literal -offset indent
- This is a normal paragraph:
-
- This is a code block.
- .Ed
- .Pp
- .Nm
- will generate:
- .Bd -literal -offset indent
- <p>This is a normal paragraph:</p>
-
- <pre><code>This is a code block.
- </code></pre>
- .Ed
- .Pp
- One level of indentation -- 4 spaces or 1 tab -- is removed from each
- line of the code block. For example, this:
- .Bd -literal -offset indent
- Here is an example of AppleScript:
-
- tell application "Foo"
- beep
- end tell
- .Ed
- .Pp
- will turn into:
- .Bd -literal -offset indent
- <p>Here is an example of AppleScript:</p>
-
- <pre><code>tell application "Foo"
- beep
- end tell
- </code></pre>
- .Ed
- .Pp
- A code block continues until it reaches a line that is not indented
- (or the end of the article).
- .Pp
- 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:
- .Bd -literal -offset indent
- <div class="footer">
- © 2004 Foo Corporation
- </div>
- .Ed
- .Pp
- will turn into:
- .Bd -literal -offset indent
- <pre><code><div class="footer">
- &copy; 2004 Foo Corporation
- </div>
- </code></pre>
- .Ed
- .Pp
- 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.
- .Ss 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:
- .Bd -literal -offset indent
- * * *
-
- ***
-
- *****
-
- - - -
-
- ---------------------------------------
- .Ed
- .Pp
- .Sh Span Elements
- .Ss Links
- .Nm
- supports two style of links:
- .Em inline
- and
- .Em reference .
- .Pp
- In both styles, the link text is delimited by [square brackets].
- .Pp
- 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:
- .Bd -literal -offset indent
- This is [an example](http://example.com/ "Title") inline link.
-
- [This link](http://example.net/) has no title attribute.
- .Ed
- .Pp
- Will produce:
- .Bd -literal -offset indent
- <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>
- .Ed
- .Pp
- If you're referring to a local resource on the same server, you can
- use relative paths:
- .Bd -literal -offset indent
- See my [About](/about/) page for details.
- .Ed
- .Pp
- Reference-style links use a second set of square brackets, inside
- which you place a label of your choosing to identify the link:
- .Bd -literal -offset indent
- This is [an example][id] reference-style link.
- .Ed
- .Pp
- You can optionally use a space to separate the sets of brackets:
- .Bd -literal -offset indent
- This is [an example] [id] reference-style link.
- .Ed
- .Pp
- Then, anywhere in the document, you define your link label like this,
- on a line by itself:
- .Bd -literal -offset indent
- [id]: http://example.com/ "Optional Title Here"
- .Ed
- .Pp
- That is:
- .Bl -bullet
- .It
- Square brackets containing the link identifier (optionally
- indented from the left margin using up to three spaces);
- .It
- followed by a colon;
- .It
- followed by one or more spaces (or tabs);
- .It
- followed by the URL for the link;
- .It
- optionally followed by a title attribute for the link, enclosed
- in double or single quotes, or enclosed in parentheses.
- .El
- .Pp
- The following three link definitions are equivalent:
- .Bd -literal -offset indent
- [foo]: http://example.com/ "Optional Title Here"
- [foo]: http://example.com/ 'Optional Title Here'
- [foo]: http://example.com/ (Optional Title Here)
- .Ed
- .Pp
- .Em Note :
- There is a known bug in Markdown.pl 1.0.1 which prevents
- single quotes from being used to delimit link titles.
- .Pp
- The link URL may, optionally, be surrounded by angle brackets:
- .Bd -literal -offset indent
- [id]: <http://example.com/> "Optional Title Here"
- .Ed
- .Pp
- 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:
- .Bd -literal -offset indent
- [id]: http://example.com/longish/path/to/resource/here
- "Optional Title Here"
- .Ed
- .Pp
- Link definitions are only used for creating links during Markdown
- processing, and are stripped from your document in the HTML output.
- .Pp
- Link definition names may constist of letters, numbers, spaces, and
- punctuation -- but they are
- .Em not
- case sensitive. E.g. these two
- links:
- .Bd -literal -offset indent
- [link text][a]
- [link text][A]
- .Ed
- .Pp
- are equivalent.
- .Pp
- The
- .Em 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
- .Qq Google
- to the google.com web site, you could simply write:
- .Bd -literal -offset indent
- [Google][]
- .Ed
- .Pp
- And then define the link:
- .Bd -literal -offset indent
- [Google]: http://google.com/
- .Ed
- .Pp
- Because link names may contain spaces, this shortcut even works for
- multiple words in the link text:
- .Bd -literal -offset indent
- Visit [Daring Fireball][] for more information.
- .Ed
- .Pp
- And then define the link:
- .Bd -literal -offset indent
- [Daring Fireball]: http://daringfireball.net/
- .Ed
- .Pp
- 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.
- .Pp
- Here's an example of reference links in action:
- .Bd -literal -offset indent
- 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"
- .Ed
- .Pp
- Using the implicit link name shortcut, you could instead write:
- .Bd -literal -offset indent
- 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"
- .Ed
- .Pp
- Both of the above examples will produce the following HTML output:
- .Bd -literal -offset indent
- <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>
- .Ed
- .Pp
- For comparison, here is the same paragraph written using
- Markdown's inline link style:
- .Bd -literal -offset indent
- 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").
- .Ed
- .Pp
- 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.
- .Pp
- 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.
- .Ss 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:
- .Bd -literal -offset indent
- *single asterisks*
-
- _single underscores_
-
- **double asterisks**
-
- __double underscores__
- .Ed
- .Pp
- will produce:
- .Bd -literal -offset indent
- <em>single asterisks</em>
-
- <em>single underscores</em>
-
- <strong>double asterisks</strong>
-
- <strong>double underscores</strong>
- .Ed
- .Pp
- 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.
- .Pp
- Emphasis can be used in the middle of a word:
- .Bd -literal -offset indent
- un*fucking*believable
- .Ed
- .Pp
- But if you surround an `*` or `_` with spaces, it'll be treated as a
- literal asterisk or underscore.
- .Pp
- 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:
- .Bd -literal -offset indent
- \\*this text is surrounded by literal asterisks\\*
- .Ed
- .Pp
- .Ss 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:
- .Bd -literal -offset indent
- Use the `printf()` function.
- .Ed
- .Pp
- will produce:
- .Bd -literal -offset indent
- <p>Use the <code>printf()</code> function.</p>
- .Ed
- .Pp
- To include a literal backtick character within a code span, you can use
- multiple backticks as the opening and closing delimiters:
- .Bd -literal -offset indent
- ``There is a literal backtick (`) here.``
- .Ed
- .Pp
- which will produce this:
- .Bd -literal -offset indent
- <p><code>There is a literal backtick (`) here.</code></p>
- .Ed
- .Pp
- 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:
- .Bd -literal -offset indent
- A single backtick in a code span: `` ` ``
-
- A backtick-delimited string in a code span: `` `foo` ``
- .Ed
- .Pp
- will produce:
- .Bd -literal -offset indent
- <p>A single backtick in a code span: <code>`</code></p>
-
- <p>A backtick-delimited string in a code span: <code>`foo`</code></p>
- .Ed
- .Pp
- 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:
- .Bd -literal -offset indent
- Please don't use any `<blink>` tags.
- .Ed
- .Pp
- into:
- .Bd -literal -offset indent
- <p>Please don't use any <code><blink></code> tags.</p>
- .Ed
- .Pp
- You can write this:
- .Bd -literal -offset indent
- `—` is the decimal-encoded equivalent of `—`.
- .Ed
- .Pp
- to produce:
- .Bd -literal -offset indent
- <p><code>&#8212;</code> is the decimal-encoded
- equivalent of <code>&mdash;</code>.</p>
- .Ed
- .Pp
- .Ss Images
- Admittedly, it's fairly difficult to devise a
- .Qq natural
- syntax for placing images into a plain text document format.
- .Pp
- Markdown uses an image syntax that is intended to resemble the syntax
- for links, allowing for two styles:
- .Em inline
- and
- .Em reference .
- .Pp
- Inline image syntax looks like this:
- .Bd -literal -offset indent
- ![Alt text](/path/to/img.jpg)
-
- ![Alt text](/path/to/img.jpg =Optional size "Optional title")
- .Ed
- .Pp
- That is:
- .Bl -bullet
- .It
- An exclamation mark: `!`;
- .It
- followed by a set of square brackets, containing the `alt`
- attribute text for the image;
- .It
- followed by a set of parentheses, containing the URL or path to
- the image, an optional `size` attribute (in
- .Ar width Li c Ar height
- format) prefixed with a `=`,
- and an optional `title` attribute enclosed in double
- or single quotes.
- .El
- .Pp
- Reference-style image syntax looks like this:
- .Bd -literal -offset indent
- ![Alt text][id]
- .Ed
- .Pp
- Where
- .Qq id
- is the name of a defined image reference. Image references
- are defined using syntax identical to link references:
- .Bd -literal -offset indent
- [id]: url/to/image =Optional size "Optional title attribute"
- .Ed
- .Pp
- .Sh Miscellaneous
- .Ss Automatic Links
- .Nm
- supports a shortcut style for creating
- .Qq 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:
- .Bd -literal -offset indent
- <http://example.com/>
- .Ed
- .Pp
- .Nm
- will turn this into:
- .Bd -literal -offset indent
- <a href="http://example.com/">http://example.com/</a>
- .Ed
- .Pp
- 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:
- .Bd -literal -offset indent
- <address@example.com>
- .Ed
- .Pp
- into something like this:
- .Bd -literal -offset indent
- <a href="mailto:addre
- ss@example.co
- m">address@exa
- mple.com</a>
- .Ed
- .Pp
- which will render in a browser as a clickable link to
- .Qq address@example.com .
- .Pp
- (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.)
- .Ss Backslash Escapes
- .Nm
- 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:
- .Bd -literal -offset indent
- \\*literal asterisks\\*
- .Ed
- .Pp
- .Nm
- provides backslash escapes for the following characters:
- .Bl -tag -compact
- .It \&\
- backslash
- .It \`
- backtick
- .It *
- asterisk
- .It _
- underscore
- .It \{\}
- curly braces
- .It []
- square brackets
- .It ()
- parentheses
- .It #
- hash mark
- .It +
- plus sign
- .It \-
- minus sign (hyphen)
- .It \.
- dot
- .It \!
- exclamation mark
- .El
- .Sh BUGS
- .Nm
- assumes that tabs are set to 4 spaces.
- .Sh AUTHOR
- John Gruber
- .%T http://daringfireball.net/
- .Sh SEE ALSO
- .Xr markdown 1 ,
- .Xr markdown 3 ,
- .Xr mkd-callbacks 3 ,
- .Xr mkd-functions 3 ,
- .Xr mkd-extensions 7 .
- .Pp
- .%T http://daringfireball.net/projects/markdown
- .br
- .%T http://docutils.sourceforge.net/mirror/setext.html
- .br
- .%T http://www.aaronsw.com/2002/atx/
- .br
- .%T http://textism.com/tools/textile/
- .br
- .%T http://docutils.sourceforge.net/rst.html
- .br
- .%T http://www.triptico.com/software/grutatxt.html
- .br
- .%T http://ettext.taint.org/doc/
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