1<h1>Markdown: Syntax</h1> 2<ul id="ProjectSubmenu"> 3 <li><a href="/projects/markdown/" title="Markdown Project Page">Main</a></li> 4 <li><a href="/projects/markdown/basics" title="Markdown Basics">Basics</a></li> 5 <li><a class="selected" title="Markdown Syntax Documentation">Syntax</a></li> 6 <li><a href="/projects/markdown/license" title="Pricing and License Information">License</a></li> 7 <li><a href="/projects/markdown/dingus" title="Online Markdown Web Form">Dingus</a></li> 8</ul> 9 10<ul> 11<li><a href="#overview">Overview</a><ul> 12<li><a href="#philosophy">Philosophy</a></li> 13<li><a href="#html">Inline HTML</a></li> 14<li><a href="#autoescape">Automatic Escaping for Special Characters</a></li> 15</ul> 16</li> 17<li><a href="#block">Block Elements</a><ul> 18<li><a href="#p">Paragraphs and Line Breaks</a></li> 19<li><a href="#header">Headers</a></li> 20<li><a href="#blockquote">Blockquotes</a></li> 21<li><a href="#list">Lists</a></li> 22<li><a href="#precode">Code Blocks</a></li> 23<li><a href="#hr">Horizontal Rules</a></li> 24</ul> 25</li> 26<li><a href="#span">Span Elements</a><ul> 27<li><a href="#link">Links</a></li> 28<li><a href="#em">Emphasis</a></li> 29<li><a href="#code">Code</a></li> 30<li><a href="#img">Images</a></li> 31</ul> 32</li> 33<li><a href="#misc">Miscellaneous</a><ul> 34<li><a href="#backslash">Backslash Escapes</a></li> 35<li><a href="#autolink">Automatic Links</a></li> 36</ul> 37</li> 38</ul> 39<p><strong>Note:</strong> This document is itself written using Markdown; you 40can <a href="/projects/markdown/syntax.text">see the source for it by adding '.text' to the URL</a>.</p> 41<hr /> 42<h2 id="overview">Overview</h2> 43 44<h3 id="philosophy">Philosophy</h3> 45 46<p>Markdown is intended to be as easy-to-read and easy-to-write as is feasible.</p> 47<p>Readability, however, is emphasized above all else. A Markdown-formatted 48document should be publishable as-is, as plain text, without looking 49like it's been marked up with tags or formatting instructions. While 50Markdown's syntax has been influenced by several existing text-to-HTML 51filters -- including <a href="http://docutils.sourceforge.net/mirror/setext.html">Setext</a>, <a href="http://www.aaronsw.com/2002/atx/">atx</a>, <a href="http://textism.com/tools/textile/">Textile</a>, <a href="http://docutils.sourceforge.net/rst.html">reStructuredText</a>, 52<a href="http://www.triptico.com/software/grutatxt.html">Grutatext</a>, and <a href="http://ettext.taint.org/doc/">EtText</a> -- the single biggest source of 53inspiration for Markdown's syntax is the format of plain text email.</p> 54<p>To this end, Markdown's syntax is comprised entirely of punctuation 55characters, which punctuation characters have been carefully chosen so 56as to look like what they mean. E.g., asterisks around a word actually 57look like *emphasis*. Markdown lists look like, well, lists. Even 58blockquotes look like quoted passages of text, assuming you've ever 59used email.</p> 60<h3 id="html">Inline HTML</h3> 61 62<p>Markdown's syntax is intended for one purpose: to be used as a 63format for <em>writing</em> for the web.</p> 64<p>Markdown is not a replacement for HTML, or even close to it. Its 65syntax is very small, corresponding only to a very small subset of 66HTML tags. The idea is <em>not</em> to create a syntax that makes it easier 67to insert HTML tags. In my opinion, HTML tags are already easy to 68insert. The idea for Markdown is to make it easy to read, write, and 69edit prose. HTML is a <em>publishing</em> format; Markdown is a <em>writing</em> 70format. Thus, Markdown's formatting syntax only addresses issues that 71can be conveyed in plain text.</p> 72<p>For any markup that is not covered by Markdown's syntax, you simply 73use HTML itself. There's no need to preface it or delimit it to 74indicate that you're switching from Markdown to HTML; you just use 75the tags.</p> 76<p>The only restrictions are that block-level HTML elements -- e.g. <code><div></code>, 77<code><table></code>, <code><pre></code>, <code><p></code>, etc. -- must be separated from surrounding 78content by blank lines, and the start and end tags of the block should 79not be indented with tabs or spaces. Markdown is smart enough not 80to add extra (unwanted) <code><p></code> tags around HTML block-level tags.</p> 81<p>For example, to add an HTML table to a Markdown article:</p> 82<pre><code>This is a regular paragraph. 83 84<table> 85 <tr> 86 <td>Foo</td> 87 </tr> 88</table> 89 90This is another regular paragraph. 91</code></pre> 92<p>Note that Markdown formatting syntax is not processed within block-level 93HTML tags. E.g., you can't use Markdown-style <code>*emphasis*</code> inside an 94HTML block.</p> 95<p>Span-level HTML tags -- e.g. <code><span></code>, <code><cite></code>, or <code><del></code> -- can be 96used anywhere in a Markdown paragraph, list item, or header. If you 97want, you can even use HTML tags instead of Markdown formatting; e.g. if 98you'd prefer to use HTML <code><a></code> or <code><img></code> tags instead of Markdown's 99link or image syntax, go right ahead.</p> 100<p>Unlike block-level HTML tags, Markdown syntax <em>is</em> processed within 101span-level tags.</p> 102<h3 id="autoescape">Automatic Escaping for Special Characters</h3> 103 104<p>In HTML, there are two characters that demand special treatment: <code><</code> 105and <code>&</code>. Left angle brackets are used to start tags; ampersands are 106used to denote HTML entities. If you want to use them as literal 107characters, you must escape them as entities, e.g. <code>&lt;</code>, and 108<code>&amp;</code>.</p> 109<p>Ampersands in particular are bedeviling for web writers. If you want to 110write about 'AT&T', you need to write '<code>AT&amp;T</code>'. You even need to 111escape ampersands within URLs. Thus, if you want to link to:</p> 112<pre><code>http://images.google.com/images?num=30&q=larry+bird 113</code></pre> 114<p>you need to encode the URL as:</p> 115<pre><code>http://images.google.com/images?num=30&q=larry+bird 116</code></pre> 117<p>in your anchor tag <code>href</code> attribute. Needless to say, this is easy to 118forget, and is probably the single most common source of HTML validation 119errors in otherwise well-marked-up web sites.</p> 120<p>Markdown allows you to use these characters naturally, taking care of 121all the necessary escaping for you. If you use an ampersand as part of 122an HTML entity, it remains unchanged; otherwise it will be translated 123into <code>&amp;</code>.</p> 124<p>So, if you want to include a copyright symbol in your article, you can write:</p> 125<pre><code>&copy; 126</code></pre> 127<p>and Markdown will leave it alone. But if you write:</p> 128<pre><code>AT&T 129</code></pre> 130<p>Markdown will translate it to:</p> 131<pre><code>AT&amp;T 132</code></pre> 133<p>Similarly, because Markdown supports <a href="#html">inline HTML</a>, if you use 134angle brackets as delimiters for HTML tags, Markdown will treat them as 135such. But if you write:</p> 136<pre><code>4 < 5 137</code></pre> 138<p>Markdown will translate it to:</p> 139<pre><code>4 &lt; 5 140</code></pre> 141<p>However, inside Markdown code spans and blocks, angle brackets and 142ampersands are <em>always</em> encoded automatically. This makes it easy to use 143Markdown to write about HTML code. (As opposed to raw HTML, which is a 144terrible format for writing about HTML syntax, because every single <code><</code> 145and <code>&</code> in your example code needs to be escaped.)</p> 146<hr /> 147<h2 id="block">Block Elements</h2> 148 149<h3 id="p">Paragraphs and Line Breaks</h3> 150 151<p>A paragraph is simply one or more consecutive lines of text, separated 152by one or more blank lines. (A blank line is any line that looks like a 153blank line -- a line containing nothing but spaces or tabs is considered 154blank.) Normal paragraphs should not be intended with spaces or tabs.</p> 155<p>The implication of the "one or more consecutive lines of text" rule is 156that Markdown supports "hard-wrapped" text paragraphs. This differs 157significantly from most other text-to-HTML formatters (including Movable 158Type's "Convert Line Breaks" option) which translate every line break 159character in a paragraph into a <code><br /></code> tag.</p> 160<p>When you <em>do</em> want to insert a <code><br /></code> break tag using Markdown, you 161end a line with two or more spaces, then type return.</p> 162<p>Yes, this takes a tad more effort to create a <code><br /></code>, but a simplistic 163"every line break is a <code><br /></code>" rule wouldn't work for Markdown. 164Markdown's email-style <a href="#blockquote">blockquoting</a> and multi-paragraph <a href="#list">list items</a> 165work best -- and look better -- when you format them with hard breaks.</p> 166<h3 id="header">Headers</h3> 167 168<p>Markdown supports two styles of headers, <a href="http://docutils.sourceforge.net/mirror/setext.html">Setext</a> and <a href="http://www.aaronsw.com/2002/atx/">atx</a>.</p> 169<p>Setext-style headers are "underlined" using equal signs (for first-level 170headers) and dashes (for second-level headers). For example:</p> 171<pre><code>This is an H1 172============= 173 174This is an H2 175------------- 176</code></pre> 177<p>Any number of underlining <code>=</code>'s or <code>-</code>'s will work.</p> 178<p>Atx-style headers use 1-6 hash characters at the start of the line, 179corresponding to header levels 1-6. For example:</p> 180<pre><code># This is an H1 181 182## This is an H2 183 184###### This is an H6 185</code></pre> 186<p>Optionally, you may "close" atx-style headers. This is purely 187cosmetic -- you can use this if you think it looks better. The 188closing hashes don't even need to match the number of hashes 189used to open the header. (The number of opening hashes 190determines the header level.) :</p> 191<pre><code># This is an H1 # 192 193## This is an H2 ## 194 195### This is an H3 ###### 196</code></pre> 197<h3 id="blockquote">Blockquotes</h3> 198 199<p>Markdown uses email-style <code>></code> characters for blockquoting. If you're 200familiar with quoting passages of text in an email message, then you 201know how to create a blockquote in Markdown. It looks best if you hard 202wrap the text and put a <code>></code> before every line:</p> 203<pre><code>> This is a blockquote with two paragraphs. Lorem ipsum dolor sit amet, 204> consectetuer adipiscing elit. Aliquam hendrerit mi posuere lectus. 205> Vestibulum enim wisi, viverra nec, fringilla in, laoreet vitae, risus. 206> 207> Donec sit amet nisl. Aliquam semper ipsum sit amet velit. Suspendisse 208> id sem consectetuer libero luctus adipiscing. 209</code></pre> 210<p>Markdown allows you to be lazy and only put the <code>></code> before the first 211line of a hard-wrapped paragraph:</p> 212<pre><code>> This is a blockquote with two paragraphs. Lorem ipsum dolor sit amet, 213consectetuer adipiscing elit. Aliquam hendrerit mi posuere lectus. 214Vestibulum enim wisi, viverra nec, fringilla in, laoreet vitae, risus. 215 216> Donec sit amet nisl. Aliquam semper ipsum sit amet velit. Suspendisse 217id sem consectetuer libero luctus adipiscing. 218</code></pre> 219<p>Blockquotes can be nested (i.e. a blockquote-in-a-blockquote) by 220adding additional levels of <code>></code>:</p> 221<pre><code>> This is the first level of quoting. 222> 223> > This is nested blockquote. 224> 225> Back to the first level. 226</code></pre> 227<p>Blockquotes can contain other Markdown elements, including headers, lists, 228and code blocks:</p> 229<pre><code>> ## This is a header. 230> 231> 1. This is the first list item. 232> 2. This is the second list item. 233> 234> Here's some example code: 235> 236> return shell_exec("echo $input | $markdown_script"); 237</code></pre> 238<p>Any decent text editor should make email-style quoting easy. For 239example, with BBEdit, you can make a selection and choose Increase 240Quote Level from the Text menu.</p> 241<h3 id="list">Lists</h3> 242 243<p>Markdown supports ordered (numbered) and unordered (bulleted) lists.</p> 244<p>Unordered lists use asterisks, pluses, and hyphens -- interchangably 245-- as list markers:</p> 246<pre><code>* Red 247* Green 248* Blue 249</code></pre> 250<p>is equivalent to:</p> 251<pre><code>+ Red 252+ Green 253+ Blue 254</code></pre> 255<p>and:</p> 256<pre><code>- Red 257- Green 258- Blue 259</code></pre> 260<p>Ordered lists use numbers followed by periods:</p> 261<pre><code>1. Bird 2622. McHale 2633. Parish 264</code></pre> 265<p>It's important to note that the actual numbers you use to mark the 266list have no effect on the HTML output Markdown produces. The HTML 267Markdown produces from the above list is:</p> 268<pre><code><ol> 269<li>Bird</li> 270<li>McHale</li> 271<li>Parish</li> 272</ol> 273</code></pre> 274<p>If you instead wrote the list in Markdown like this:</p> 275<pre><code>1. Bird 2761. McHale 2771. Parish 278</code></pre> 279<p>or even:</p> 280<pre><code>3. Bird 2811. McHale 2828. Parish 283</code></pre> 284<p>you'd get the exact same HTML output. The point is, if you want to, 285you can use ordinal numbers in your ordered Markdown lists, so that 286the numbers in your source match the numbers in your published HTML. 287But if you want to be lazy, you don't have to.</p> 288<p>If you do use lazy list numbering, however, you should still start the 289list with the number 1. At some point in the future, Markdown may support 290starting ordered lists at an arbitrary number.</p> 291<p>List markers typically start at the left margin, but may be indented by 292up to three spaces. List markers must be followed by one or more spaces 293or a tab.</p> 294<p>To make lists look nice, you can wrap items with hanging indents:</p> 295<pre><code>* Lorem ipsum dolor sit amet, consectetuer adipiscing elit. 296 Aliquam hendrerit mi posuere lectus. Vestibulum enim wisi, 297 viverra nec, fringilla in, laoreet vitae, risus. 298* Donec sit amet nisl. Aliquam semper ipsum sit amet velit. 299 Suspendisse id sem consectetuer libero luctus adipiscing. 300</code></pre> 301<p>But if you want to be lazy, you don't have to:</p> 302<pre><code>* Lorem ipsum dolor sit amet, consectetuer adipiscing elit. 303Aliquam hendrerit mi posuere lectus. Vestibulum enim wisi, 304viverra nec, fringilla in, laoreet vitae, risus. 305* Donec sit amet nisl. Aliquam semper ipsum sit amet velit. 306Suspendisse id sem consectetuer libero luctus adipiscing. 307</code></pre> 308<p>If list items are separated by blank lines, Markdown will wrap the 309items in <code><p></code> tags in the HTML output. For example, this input:</p> 310<pre><code>* Bird 311* Magic 312</code></pre> 313<p>will turn into:</p> 314<pre><code><ul> 315<li>Bird</li> 316<li>Magic</li> 317</ul> 318</code></pre> 319<p>But this:</p> 320<pre><code>* Bird 321 322* Magic 323</code></pre> 324<p>will turn into:</p> 325<pre><code><ul> 326<li><p>Bird</p></li> 327<li><p>Magic</p></li> 328</ul> 329</code></pre> 330<p>List items may consist of multiple paragraphs. Each subsequent 331paragraph in a list item must be intended by either 4 spaces 332or one tab:</p> 333<pre><code>1. This is a list item with two paragraphs. Lorem ipsum dolor 334 sit amet, consectetuer adipiscing elit. Aliquam hendrerit 335 mi posuere lectus. 336 337 Vestibulum enim wisi, viverra nec, fringilla in, laoreet 338 vitae, risus. Donec sit amet nisl. Aliquam semper ipsum 339 sit amet velit. 340 3412. Suspendisse id sem consectetuer libero luctus adipiscing. 342</code></pre> 343<p>It looks nice if you indent every line of the subsequent 344paragraphs, but here again, Markdown will allow you to be 345lazy:</p> 346<pre><code>* This is a list item with two paragraphs. 347 348 This is the second paragraph in the list item. You're 349only required to indent the first line. Lorem ipsum dolor 350sit amet, consectetuer adipiscing elit. 351 352* Another item in the same list. 353</code></pre> 354<p>To put a blockquote within a list item, the blockquote's <code>></code> 355delimiters need to be indented:</p> 356<pre><code>* A list item with a blockquote: 357 358 > This is a blockquote 359 > inside a list item. 360</code></pre> 361<p>To put a code block within a list item, the code block needs 362to be indented <em>twice</em> -- 8 spaces or two tabs:</p> 363<pre><code>* A list item with a code block: 364 365 <code goes here> 366</code></pre> 367<p>It's worth noting that it's possible to trigger an ordered list by 368accident, by writing something like this:</p> 369<pre><code>1986. What a great season. 370</code></pre> 371<p>In other words, a <em>number-period-space</em> sequence at the beginning of a 372line. To avoid this, you can backslash-escape the period:</p> 373<pre><code>1986\. What a great season. 374</code></pre> 375<h3 id="precode">Code Blocks</h3> 376 377<p>Pre-formatted code blocks are used for writing about programming or 378markup source code. Rather than forming normal paragraphs, the lines 379of a code block are interpreted literally. Markdown wraps a code block 380in both <code><pre></code> and <code><code></code> tags.</p> 381<p>To produce a code block in Markdown, simply indent every line of the 382block by at least 4 spaces or 1 tab. For example, given this input:</p> 383<pre><code>This is a normal paragraph: 384 385 This is a code block. 386</code></pre> 387<p>Markdown will generate:</p> 388<pre><code><p>This is a normal paragraph:</p> 389 390<pre><code>This is a code block. 391</code></pre> 392</code></pre> 393<p>One level of indentation -- 4 spaces or 1 tab -- is removed from each 394line of the code block. For example, this:</p> 395<pre><code>Here is an example of AppleScript: 396 397 tell application "Foo" 398 beep 399 end tell 400</code></pre> 401<p>will turn into:</p> 402<pre><code><p>Here is an example of AppleScript:</p> 403 404<pre><code>tell application "Foo" 405 beep 406end tell 407</code></pre> 408</code></pre> 409<p>A code block continues until it reaches a line that is not indented 410(or the end of the article).</p> 411<p>Within a code block, ampersands (<code>&</code>) and angle brackets (<code><</code> and <code>></code>) 412are automatically converted into HTML entities. This makes it very 413easy to include example HTML source code using Markdown -- just paste 414it and indent it, and Markdown will handle the hassle of encoding the 415ampersands and angle brackets. For example, this:</p> 416<pre><code> <div class="footer"> 417 &copy; 2004 Foo Corporation 418 </div> 419</code></pre> 420<p>will turn into:</p> 421<pre><code><pre><code>&lt;div class="footer"&gt; 422 &amp;copy; 2004 Foo Corporation 423&lt;/div&gt; 424</code></pre> 425</code></pre> 426<p>Regular Markdown syntax is not processed within code blocks. E.g., 427asterisks are just literal asterisks within a code block. This means 428it's also easy to use Markdown to write about Markdown's own syntax.</p> 429<h3 id="hr">Horizontal Rules</h3> 430 431<p>You can produce a horizontal rule tag (<code><hr /></code>) by placing three or 432more hyphens, asterisks, or underscores on a line by themselves. If you 433wish, you may use spaces between the hyphens or asterisks. Each of the 434following lines will produce a horizontal rule:</p> 435<pre><code>* * * 436 437*** 438 439***** 440 441- - - 442 443--------------------------------------- 444 445_ _ _ 446</code></pre> 447<hr /> 448<h2 id="span">Span Elements</h2> 449 450<h3 id="link">Links</h3> 451 452<p>Markdown supports two style of links: <em>inline</em> and <em>reference</em>.</p> 453<p>In both styles, the link text is delimited by [square brackets].</p> 454<p>To create an inline link, use a set of regular parentheses immediately 455after the link text's closing square bracket. Inside the parentheses, 456put the URL where you want the link to point, along with an <em>optional</em> 457title for the link, surrounded in quotes. For example:</p> 458<pre><code>This is [an example](http://example.com/ "Title") inline link. 459 460[This link](http://example.net/) has no title attribute. 461</code></pre> 462<p>Will produce:</p> 463<pre><code><p>This is <a href="http://example.com/" title="Title"> 464an example</a> inline link.</p> 465 466<p><a href="http://example.net/">This link</a> has no 467title attribute.</p> 468</code></pre> 469<p>If you're referring to a local resource on the same server, you can 470use relative paths:</p> 471<pre><code>See my [About](/about/) page for details. 472</code></pre> 473<p>Reference-style links use a second set of square brackets, inside 474which you place a label of your choosing to identify the link:</p> 475<pre><code>This is [an example][id] reference-style link. 476</code></pre> 477<p>You can optionally use a space to separate the sets of brackets:</p> 478<pre><code>This is [an example] [id] reference-style link. 479</code></pre> 480<p>Then, anywhere in the document, you define your link label like this, 481on a line by itself:</p> 482<pre><code>[id]: http://example.com/ "Optional Title Here" 483</code></pre> 484<p>That is:</p> 485<ul> 486<li>Square brackets containing the link identifier (optionally 487indented from the left margin using up to three spaces);</li> 488<li>followed by a colon;</li> 489<li>followed by one or more spaces (or tabs);</li> 490<li>followed by the URL for the link;</li> 491<li>optionally followed by a title attribute for the link, enclosed 492in double or single quotes.</li> 493</ul> 494<p>The link URL may, optionally, be surrounded by angle brackets:</p> 495<pre><code>[id]: <http://example.com/>; "Optional Title Here" 496</code></pre> 497<p>You can put the title attribute on the next line and use extra spaces 498or tabs for padding, which tends to look better with longer URLs:</p> 499<pre><code>[id]: http://example.com/longish/path/to/resource/here 500 "Optional Title Here" 501</code></pre> 502<p>Link definitions are only used for creating links during Markdown 503processing, and are stripped from your document in the HTML output.</p> 504<p>Link definition names may constist of letters, numbers, spaces, and punctuation -- but they are <em>not</em> case sensitive. E.g. these two links:</p> 505<pre><code>[link text][a] 506[link text][A] 507</code></pre> 508<p>are equivalent.</p> 509<p>The <em>implicit link name</em> shortcut allows you to omit the name of the 510link, in which case the link text itself is used as the name. 511Just use an empty set of square brackets -- e.g., to link the word 512"Google" to the google.com web site, you could simply write:</p> 513<pre><code>[Google][] 514</code></pre> 515<p>And then define the link:</p> 516<pre><code>[Google]: http://google.com/ 517</code></pre> 518<p>Because link names may contain spaces, this shortcut even works for 519multiple words in the link text:</p> 520<pre><code>Visit [Daring Fireball][] for more information. 521</code></pre> 522<p>And then define the link:</p> 523<pre><code>[Daring Fireball]: http://daringfireball.net/ 524</code></pre> 525<p>Link definitions can be placed anywhere in your Markdown document. I 526tend to put them immediately after each paragraph in which they're 527used, but if you want, you can put them all at the end of your 528document, sort of like footnotes.</p> 529<p>Here's an example of reference links in action:</p> 530<pre><code>I get 10 times more traffic from [Google] [1] than from 531[Yahoo] [2] or [MSN] [3]. 532 533 [1]: http://google.com/ "Google" 534 [2]: http://search.yahoo.com/ "Yahoo Search" 535 [3]: http://search.msn.com/ "MSN Search" 536</code></pre> 537<p>Using the implicit link name shortcut, you could instead write:</p> 538<pre><code>I get 10 times more traffic from [Google][] than from 539[Yahoo][] or [MSN][]. 540 541 [google]: http://google.com/ "Google" 542 [yahoo]: http://search.yahoo.com/ "Yahoo Search" 543 [msn]: http://search.msn.com/ "MSN Search" 544</code></pre> 545<p>Both of the above examples will produce the following HTML output:</p> 546<pre><code><p>I get 10 times more traffic from <a href="http://google.com/" 547title="Google">Google</a> than from 548<a href="http://search.yahoo.com/" title="Yahoo Search">Yahoo</a> 549or <a href="http://search.msn.com/" title="MSN Search">MSN</a>.</p> 550</code></pre> 551<p>For comparison, here is the same paragraph written using 552Markdown's inline link style:</p> 553<pre><code>I get 10 times more traffic from [Google](http://google.com/ "Google") 554than from [Yahoo](http://search.yahoo.com/ "Yahoo Search") or 555[MSN](http://search.msn.com/ "MSN Search"). 556</code></pre> 557<p>The point of reference-style links is not that they're easier to 558write. The point is that with reference-style links, your document 559source is vastly more readable. Compare the above examples: using 560reference-style links, the paragraph itself is only 81 characters 561long; with inline-style links, it's 176 characters; and as raw HTML, 562it's 234 characters. In the raw HTML, there's more markup than there 563is text.</p> 564<p>With Markdown's reference-style links, a source document much more 565closely resembles the final output, as rendered in a browser. By 566allowing you to move the markup-related metadata out of the paragraph, 567you can add links without interrupting the narrative flow of your 568prose.</p> 569<h3 id="em">Emphasis</h3> 570 571<p>Markdown treats asterisks (<code>*</code>) and underscores (<code>_</code>) as indicators of 572emphasis. Text wrapped with one <code>*</code> or <code>_</code> will be wrapped with an 573HTML <code><em></code> tag; double <code>*</code>'s or <code>_</code>'s will be wrapped with an HTML 574<code><strong></code> tag. E.g., this input:</p> 575<pre><code>*single asterisks* 576 577_single underscores_ 578 579**double asterisks** 580 581__double underscores__ 582</code></pre> 583<p>will produce:</p> 584<pre><code><em>single asterisks</em> 585 586<em>single underscores</em> 587 588<strong>double asterisks</strong> 589 590<strong>double underscores</strong> 591</code></pre> 592<p>You can use whichever style you prefer; the lone restriction is that 593the same character must be used to open and close an emphasis span.</p> 594<p>Emphasis can be used in the middle of a word:</p> 595<pre><code>un*fucking*believable 596</code></pre> 597<p>But if you surround an <code>*</code> or <code>_</code> with spaces, it'll be treated as a 598literal asterisk or underscore.</p> 599<p>To produce a literal asterisk or underscore at a position where it 600would otherwise be used as an emphasis delimiter, you can backslash 601escape it:</p> 602<pre><code>\*this text is surrounded by literal asterisks\* 603</code></pre> 604<h3 id="code">Code</h3> 605 606<p>To indicate a span of code, wrap it with backtick quotes (<code>`</code>). 607Unlike a pre-formatted code block, a code span indicates code within a 608normal paragraph. For example:</p> 609<pre><code>Use the `printf()` function. 610</code></pre> 611<p>will produce:</p> 612<pre><code><p>Use the <code>printf()</code> function.</p> 613</code></pre> 614<p>To include a literal backtick character within a code span, you can use 615multiple backticks as the opening and closing delimiters:</p> 616<pre><code>``There is a literal backtick (`) here.`` 617</code></pre> 618<p>which will produce this:</p> 619<pre><code><p><code>There is a literal backtick (`) here.</code></p> 620</code></pre> 621<p>The backtick delimiters surrounding a code span may include spaces -- 622one after the opening, one before the closing. This allows you to place 623literal backtick characters at the beginning or end of a code span:</p> 624<pre><code>A single backtick in a code span: `` ` `` 625 626A backtick-delimited string in a code span: `` `foo` `` 627</code></pre> 628<p>will produce:</p> 629<pre><code><p>A single backtick in a code span: <code>`</code></p> 630 631<p>A backtick-delimited string in a code span: <code>`foo`</code></p> 632</code></pre> 633<p>With a code span, ampersands and angle brackets are encoded as HTML 634entities automatically, which makes it easy to include example HTML 635tags. Markdown will turn this:</p> 636<pre><code>Please don't use any `<blink>` tags. 637</code></pre> 638<p>into:</p> 639<pre><code><p>Please don't use any <code>&lt;blink&gt;</code> tags.</p> 640</code></pre> 641<p>You can write this:</p> 642<pre><code>`&#8212;` is the decimal-encoded equivalent of `&mdash;`. 643</code></pre> 644<p>to produce:</p> 645<pre><code><p><code>&amp;#8212;</code> is the decimal-encoded 646equivalent of <code>&amp;mdash;</code>.</p> 647</code></pre> 648<h3 id="img">Images</h3> 649 650<p>Admittedly, it's fairly difficult to devise a "natural" syntax for 651placing images into a plain text document format.</p> 652<p>Markdown uses an image syntax that is intended to resemble the syntax 653for links, allowing for two styles: <em>inline</em> and <em>reference</em>.</p> 654<p>Inline image syntax looks like this:</p> 655<pre><code> 656 657 658</code></pre> 659<p>That is:</p> 660<ul> 661<li>An exclamation mark: <code>!</code>;</li> 662<li>followed by a set of square brackets, containing the <code>alt</code> 663attribute text for the image;</li> 664<li>followed by a set of parentheses, containing the URL or path to 665the image, and an optional <code>title</code> attribute enclosed in double 666or single quotes.</li> 667</ul> 668<p>Reference-style image syntax looks like this:</p> 669<pre><code>![Alt text][id] 670</code></pre> 671<p>Where "id" is the name of a defined image reference. Image references 672are defined using syntax identical to link references:</p> 673<pre><code>[id]: url/to/image "Optional title attribute" 674</code></pre> 675<p>As of this writing, Markdown has no syntax for specifying the 676dimensions of an image; if this is important to you, you can simply 677use regular HTML <code><img></code> tags.</p> 678<hr /> 679<h2 id="misc">Miscellaneous</h2> 680 681<h3 id="autolink">Automatic Links</h3> 682 683<p>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:</p> 684<pre><code><http://example.com/>; 685</code></pre> 686<p>Markdown will turn this into:</p> 687<pre><code><a href="http://example.com/">http://example.com/</a>; 688</code></pre> 689<p>Automatic links for email addresses work similarly, except that 690Markdown will also perform a bit of randomized decimal and hex 691entity-encoding to help obscure your address from address-harvesting 692spambots. For example, Markdown will turn this:</p> 693<pre><code><address@example.com> 694</code></pre> 695<p>into something like this:</p> 696<pre><code><a href="&#x6D;&#x61;i&#x6C;&#x74;&#x6F;:&#x61;&#x64;&#x64;&#x72;&#x65; 697&#115;&#115;&#64;&#101;&#120;&#x61;&#109;&#x70;&#x6C;e&#x2E;&#99;&#111; 698&#109;">&#x61;&#x64;&#x64;&#x72;&#x65;&#115;&#115;&#64;&#101;&#120;&#x61; 699&#109;&#x70;&#x6C;e&#x2E;&#99;&#111;&#109;</a> 700</code></pre> 701<p>which will render in a browser as a clickable link to "address@example.com".</p> 702<p>(This sort of entity-encoding trick will indeed fool many, if not 703most, address-harvesting bots, but it definitely won't fool all of 704them. It's better than nothing, but an address published in this way 705will probably eventually start receiving spam.)</p> 706<h3 id="backslash">Backslash Escapes</h3> 707 708<p>Markdown allows you to use backslash escapes to generate literal 709characters which would otherwise have special meaning in Markdown's 710formatting syntax. For example, if you wanted to surround a word with 711literal asterisks (instead of an HTML <code><em></code> tag), you can backslashes 712before the asterisks, like this:</p> 713<pre><code>\*literal asterisks\* 714</code></pre> 715<p>Markdown provides backslash escapes for the following characters:</p> 716<pre><code>\ backslash 717` backtick 718* asterisk 719_ underscore 720{} curly braces 721[] square brackets 722() parentheses 723# hash mark 724+ plus sign 725- minus sign (hyphen) 726. dot 727! exclamation mark 728</code></pre>
