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<ul> 10<li><a href="#overview">Overview</a><ul> 11<li><a href="#philosophy">Philosophy</a></li> 12<li><a href="#html">Inline HTML</a></li> 13<li><a href="#autoescape">Automatic Escaping for Special Characters</a></li> 14</ul> 15</li> 16<li><a href="#block">Block Elements</a><ul> 17<li><a href="#p">Paragraphs and Line Breaks</a></li> 18<li><a href="#header">Headers</a></li> 19<li><a href="#blockquote">Blockquotes</a></li> 20<li><a href="#list">Lists</a></li> 21<li><a href="#precode">Code Blocks</a></li> 22<li><a href="#hr">Horizontal Rules</a></li> 23</ul> 24</li> 25<li><a href="#span">Span Elements</a><ul> 26<li><a href="#link">Links</a></li> 27<li><a href="#em">Emphasis</a></li> 28<li><a href="#code">Code</a></li> 29<li><a href="#img">Images</a></li> 30</ul> 31</li> 32<li><a href="#misc">Miscellaneous</a><ul> 33<li><a href="#backslash">Backslash Escapes</a></li> 34<li><a href="#autolink">Automatic Links</a></li> 35</ul> 36</li> 37</ul> 38<p><strong>Note:</strong> This document is itself written using Markdown; you 39can <a href="/projects/markdown/syntax.text">see the source for it by adding '.text' to the URL</a>.</p> 40<hr /> 41<h2 id="overview">Overview</h2> 42<h3 id="philosophy">Philosophy</h3> 43<p>Markdown is intended to be as easy-to-read and easy-to-write as is feasible.</p> 44<p>Readability, however, is emphasized above all else. A Markdown-formatted 45document should be publishable as-is, as plain text, without looking 46like it's been marked up with tags or formatting instructions. While 47Markdown's syntax has been influenced by several existing text-to-HTML 48filters -- 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>, 49<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 50inspiration for Markdown's syntax is the format of plain text email.</p> 51<p>To this end, Markdown's syntax is comprised entirely of punctuation 52characters, which punctuation characters have been carefully chosen so 53as to look like what they mean. E.g., asterisks around a word actually 54look like *emphasis*. Markdown lists look like, well, lists. Even 55blockquotes look like quoted passages of text, assuming you've ever 56used email.</p> 57<h3 id="html">Inline HTML</h3> 58<p>Markdown's syntax is intended for one purpose: to be used as a 59format for <em>writing</em> for the web.</p> 60<p>Markdown is not a replacement for HTML, or even close to it. Its 61syntax is very small, corresponding only to a very small subset of 62HTML tags. The idea is <em>not</em> to create a syntax that makes it easier 63to insert HTML tags. In my opinion, HTML tags are already easy to 64insert. The idea for Markdown is to make it easy to read, write, and 65edit prose. HTML is a <em>publishing</em> format; Markdown is a <em>writing</em> 66format. Thus, Markdown's formatting syntax only addresses issues that 67can be conveyed in plain text.</p> 68<p>For any markup that is not covered by Markdown's syntax, you simply 69use HTML itself. There's no need to preface it or delimit it to 70indicate that you're switching from Markdown to HTML; you just use 71the tags.</p> 72<p>The only restrictions are that block-level HTML elements -- e.g. <code><div></code>, 73<code><table></code>, <code><pre></code>, <code><p></code>, etc. -- must be separated from surrounding 74content by blank lines, and the start and end tags of the block should 75not be indented with tabs or spaces. Markdown is smart enough not 76to add extra (unwanted) <code><p></code> tags around HTML block-level tags.</p> 77<p>For example, to add an HTML table to a Markdown article:</p> 78<pre><code>This is a regular paragraph. 79 80<table> 81 <tr> 82 <td>Foo</td> 83 </tr> 84</table> 85 86This is another regular paragraph. 87</code></pre> 88<p>Note that Markdown formatting syntax is not processed within block-level 89HTML tags. E.g., you can't use Markdown-style <code>*emphasis*</code> inside an 90HTML block.</p> 91<p>Span-level HTML tags -- e.g. <code><span></code>, <code><cite></code>, or <code><del></code> -- can be 92used anywhere in a Markdown paragraph, list item, or header. If you 93want, you can even use HTML tags instead of Markdown formatting; e.g. if 94you'd prefer to use HTML <code><a></code> or <code><img></code> tags instead of Markdown's 95link or image syntax, go right ahead.</p> 96<p>Unlike block-level HTML tags, Markdown syntax <em>is</em> processed within 97span-level tags.</p> 98<h3 id="autoescape">Automatic Escaping for Special Characters</h3> 99<p>In HTML, there are two characters that demand special treatment: <code><</code> 100and <code>&</code>. Left angle brackets are used to start tags; ampersands are 101used to denote HTML entities. If you want to use them as literal 102characters, you must escape them as entities, e.g. <code>&lt;</code>, and 103<code>&amp;</code>.</p> 104<p>Ampersands in particular are bedeviling for web writers. If you want to 105write about 'AT&T', you need to write '<code>AT&amp;T</code>'. You even need to 106escape ampersands within URLs. Thus, if you want to link to:</p> 107<pre><code>http://images.google.com/images?num=30&q=larry+bird 108</code></pre> 109<p>you need to encode the URL as:</p> 110<pre><code>http://images.google.com/images?num=30&amp;q=larry+bird 111</code></pre> 112<p>in your anchor tag <code>href</code> attribute. Needless to say, this is easy to 113forget, and is probably the single most common source of HTML validation 114errors in otherwise well-marked-up web sites.</p> 115<p>Markdown allows you to use these characters naturally, taking care of 116all the necessary escaping for you. If you use an ampersand as part of 117an HTML entity, it remains unchanged; otherwise it will be translated 118into <code>&amp;</code>.</p> 119<p>So, if you want to include a copyright symbol in your article, you can write:</p> 120<pre><code>&copy; 121</code></pre> 122<p>and Markdown will leave it alone. But if you write:</p> 123<pre><code>AT&T 124</code></pre> 125<p>Markdown will translate it to:</p> 126<pre><code>AT&amp;T 127</code></pre> 128<p>Similarly, because Markdown supports <a href="#html">inline HTML</a>, if you use 129angle brackets as delimiters for HTML tags, Markdown will treat them as 130such. But if you write:</p> 131<pre><code>4 < 5 132</code></pre> 133<p>Markdown will translate it to:</p> 134<pre><code>4 &lt; 5 135</code></pre> 136<p>However, inside Markdown code spans and blocks, angle brackets and 137ampersands are <em>always</em> encoded automatically. This makes it easy to use 138Markdown to write about HTML code. (As opposed to raw HTML, which is a 139terrible format for writing about HTML syntax, because every single <code><</code> 140and <code>&</code> in your example code needs to be escaped.)</p> 141<hr /> 142<h2 id="block">Block Elements</h2> 143<h3 id="p">Paragraphs and Line Breaks</h3> 144<p>A paragraph is simply one or more consecutive lines of text, separated 145by one or more blank lines. (A blank line is any line that looks like a 146blank line -- a line containing nothing but spaces or tabs is considered 147blank.) Normal paragraphs should not be indented with spaces or tabs.</p> 148<p>The implication of the "one or more consecutive lines of text" rule is 149that Markdown supports "hard-wrapped" text paragraphs. This differs 150significantly from most other text-to-HTML formatters (including Movable 151Type's "Convert Line Breaks" option) which translate every line break 152character in a paragraph into a <code><br /></code> tag.</p> 153<p>When you <em>do</em> want to insert a <code><br /></code> break tag using Markdown, you 154end a line with two or more spaces, then type return.</p> 155<p>Yes, this takes a tad more effort to create a <code><br /></code>, but a simplistic 156"every line break is a <code><br /></code>" rule wouldn't work for Markdown. 157Markdown's email-style <a href="#blockquote">blockquoting</a> and multi-paragraph <a href="#list">list items</a> 158work best -- and look better -- when you format them with hard breaks.</p> 159<h3 id="header">Headers</h3> 160<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> 161<p>Setext-style headers are "underlined" using equal signs (for first-level 162headers) and dashes (for second-level headers). For example:</p> 163<pre><code>This is an H1 164============= 165 166This is an H2 167------------- 168</code></pre> 169<p>Any number of underlining <code>=</code>'s or <code>-</code>'s will work.</p> 170<p>Atx-style headers use 1-6 hash characters at the start of the line, 171corresponding to header levels 1-6. For example:</p> 172<pre><code># This is an H1 173 174## This is an H2 175 176###### This is an H6 177</code></pre> 178<p>Optionally, you may "close" atx-style headers. This is purely 179cosmetic -- you can use this if you think it looks better. The 180closing hashes don't even need to match the number of hashes 181used to open the header. (The number of opening hashes 182determines the header level.) :</p> 183<pre><code># This is an H1 # 184 185## This is an H2 ## 186 187### This is an H3 ###### 188</code></pre> 189<h3 id="blockquote">Blockquotes</h3> 190<p>Markdown uses email-style <code>></code> characters for blockquoting. If you're 191familiar with quoting passages of text in an email message, then you 192know how to create a blockquote in Markdown. It looks best if you hard 193wrap the text and put a <code>></code> before every line:</p> 194<pre><code>> This is a blockquote with two paragraphs. Lorem ipsum dolor sit amet, 195> consectetuer adipiscing elit. Aliquam hendrerit mi posuere lectus. 196> Vestibulum enim wisi, viverra nec, fringilla in, laoreet vitae, risus. 197> 198> Donec sit amet nisl. Aliquam semper ipsum sit amet velit. Suspendisse 199> id sem consectetuer libero luctus adipiscing. 200</code></pre> 201<p>Markdown allows you to be lazy and only put the <code>></code> before the first 202line of a hard-wrapped paragraph:</p> 203<pre><code>> This is a blockquote with two paragraphs. Lorem ipsum dolor sit amet, 204consectetuer adipiscing elit. Aliquam hendrerit mi posuere lectus. 205Vestibulum enim wisi, viverra nec, fringilla in, laoreet vitae, risus. 206 207> Donec sit amet nisl. Aliquam semper ipsum sit amet velit. Suspendisse 208id sem consectetuer libero luctus adipiscing. 209</code></pre> 210<p>Blockquotes can be nested (i.e. a blockquote-in-a-blockquote) by 211adding additional levels of <code>></code>:</p> 212<pre><code>> This is the first level of quoting. 213> 214> > This is nested blockquote. 215> 216> Back to the first level. 217</code></pre> 218<p>Blockquotes can contain other Markdown elements, including headers, lists, 219and code blocks:</p> 220<pre><code>> ## This is a header. 221> 222> 1. This is the first list item. 223> 2. This is the second list item. 224> 225> Here's some example code: 226> 227> return shell_exec("echo $input | $markdown_script"); 228</code></pre> 229<p>Any decent text editor should make email-style quoting easy. For 230example, with BBEdit, you can make a selection and choose Increase 231Quote Level from the Text menu.</p> 232<h3 id="list">Lists</h3> 233<p>Markdown supports ordered (numbered) and unordered (bulleted) lists.</p> 234<p>Unordered lists use asterisks, pluses, and hyphens -- interchangably 235-- as list markers:</p> 236<pre><code>* Red 237* Green 238* Blue 239</code></pre> 240<p>is equivalent to:</p> 241<pre><code>+ Red 242+ Green 243+ Blue 244</code></pre> 245<p>and:</p> 246<pre><code>- Red 247- Green 248- Blue 249</code></pre> 250<p>Ordered lists use numbers followed by periods:</p> 251<pre><code>1. Bird 2522. McHale 2533. Parish 254</code></pre> 255<p>It's important to note that the actual numbers you use to mark the 256list have no effect on the HTML output Markdown produces. The HTML 257Markdown produces from the above list is:</p> 258<pre><code><ol> 259<li>Bird</li> 260<li>McHale</li> 261<li>Parish</li> 262</ol> 263</code></pre> 264<p>If you instead wrote the list in Markdown like this:</p> 265<pre><code>1. Bird 2661. McHale 2671. Parish 268</code></pre> 269<p>or even:</p> 270<pre><code>3. Bird 2711. McHale 2728. Parish 273</code></pre> 274<p>you'd get the exact same HTML output. The point is, if you want to, 275you can use ordinal numbers in your ordered Markdown lists, so that 276the numbers in your source match the numbers in your published HTML. 277But if you want to be lazy, you don't have to.</p> 278<p>If you do use lazy list numbering, however, you should still start the 279list with the number 1. At some point in the future, Markdown may support 280starting ordered lists at an arbitrary number.</p> 281<p>List markers typically start at the left margin, but may be indented by 282up to three spaces. List markers must be followed by one or more spaces 283or a tab.</p> 284<p>To make lists look nice, you can wrap items with hanging indents:</p> 285<pre><code>* Lorem ipsum dolor sit amet, consectetuer adipiscing elit. 286 Aliquam hendrerit mi posuere lectus. Vestibulum enim wisi, 287 viverra nec, fringilla in, laoreet vitae, risus. 288* Donec sit amet nisl. Aliquam semper ipsum sit amet velit. 289 Suspendisse id sem consectetuer libero luctus adipiscing. 290</code></pre> 291<p>But if you want to be lazy, you don't have to:</p> 292<pre><code>* Lorem ipsum dolor sit amet, consectetuer adipiscing elit. 293Aliquam hendrerit mi posuere lectus. Vestibulum enim wisi, 294viverra nec, fringilla in, laoreet vitae, risus. 295* Donec sit amet nisl. Aliquam semper ipsum sit amet velit. 296Suspendisse id sem consectetuer libero luctus adipiscing. 297</code></pre> 298<p>If list items are separated by blank lines, Markdown will wrap the 299items in <code><p></code> tags in the HTML output. For example, this input:</p> 300<pre><code>* Bird 301* Magic 302</code></pre> 303<p>will turn into:</p> 304<pre><code><ul> 305<li>Bird</li> 306<li>Magic</li> 307</ul> 308</code></pre> 309<p>But this:</p> 310<pre><code>* Bird 311 312* Magic 313</code></pre> 314<p>will turn into:</p> 315<pre><code><ul> 316<li><p>Bird</p></li> 317<li><p>Magic</p></li> 318</ul> 319</code></pre> 320<p>List items may consist of multiple paragraphs. Each subsequent 321paragraph in a list item must be indented by either 4 spaces 322or one tab:</p> 323<pre><code>1. This is a list item with two paragraphs. Lorem ipsum dolor 324 sit amet, consectetuer adipiscing elit. Aliquam hendrerit 325 mi posuere lectus. 326 327 Vestibulum enim wisi, viverra nec, fringilla in, laoreet 328 vitae, risus. Donec sit amet nisl. Aliquam semper ipsum 329 sit amet velit. 330 3312. Suspendisse id sem consectetuer libero luctus adipiscing. 332</code></pre> 333<p>It looks nice if you indent every line of the subsequent 334paragraphs, but here again, Markdown will allow you to be 335lazy:</p> 336<pre><code>* This is a list item with two paragraphs. 337 338 This is the second paragraph in the list item. You're 339only required to indent the first line. Lorem ipsum dolor 340sit amet, consectetuer adipiscing elit. 341 342* Another item in the same list. 343</code></pre> 344<p>To put a blockquote within a list item, the blockquote's <code>></code> 345delimiters need to be indented:</p> 346<pre><code>* A list item with a blockquote: 347 348 > This is a blockquote 349 > inside a list item. 350</code></pre> 351<p>To put a code block within a list item, the code block needs 352to be indented <em>twice</em> -- 8 spaces or two tabs:</p> 353<pre><code>* A list item with a code block: 354 355 <code goes here> 356</code></pre> 357<p>It's worth noting that it's possible to trigger an ordered list by 358accident, by writing something like this:</p> 359<pre><code>1986. What a great season. 360</code></pre> 361<p>In other words, a <em>number-period-space</em> sequence at the beginning of a 362line. To avoid this, you can backslash-escape the period:</p> 363<pre><code>1986\. What a great season. 364</code></pre> 365<h3 id="precode">Code Blocks</h3> 366<p>Pre-formatted code blocks are used for writing about programming or 367markup source code. Rather than forming normal paragraphs, the lines 368of a code block are interpreted literally. Markdown wraps a code block 369in both <code><pre></code> and <code><code></code> tags.</p> 370<p>To produce a code block in Markdown, simply indent every line of the 371block by at least 4 spaces or 1 tab. For example, given this input:</p> 372<pre><code>This is a normal paragraph: 373 374 This is a code block. 375</code></pre> 376<p>Markdown will generate:</p> 377<pre><code><p>This is a normal paragraph:</p> 378 379<pre><code>This is a code block. 380</code></pre> 381</code></pre> 382<p>One level of indentation -- 4 spaces or 1 tab -- is removed from each 383line of the code block. For example, this:</p> 384<pre><code>Here is an example of AppleScript: 385 386 tell application "Foo" 387 beep 388 end tell 389</code></pre> 390<p>will turn into:</p> 391<pre><code><p>Here is an example of AppleScript:</p> 392 393<pre><code>tell application "Foo" 394 beep 395end tell 396</code></pre> 397</code></pre> 398<p>A code block continues until it reaches a line that is not indented 399(or the end of the article).</p> 400<p>Within a code block, ampersands (<code>&</code>) and angle brackets (<code><</code> and <code>></code>) 401are automatically converted into HTML entities. This makes it very 402easy to include example HTML source code using Markdown -- just paste 403it and indent it, and Markdown will handle the hassle of encoding the 404ampersands and angle brackets. For example, this:</p> 405<pre><code> <div class="footer"> 406 &copy; 2004 Foo Corporation 407 </div> 408</code></pre> 409<p>will turn into:</p> 410<pre><code><pre><code>&lt;div class="footer"&gt; 411 &amp;copy; 2004 Foo Corporation 412&lt;/div&gt; 413</code></pre> 414</code></pre> 415<p>Regular Markdown syntax is not processed within code blocks. E.g., 416asterisks are just literal asterisks within a code block. This means 417it's also easy to use Markdown to write about Markdown's own syntax.</p> 418<h3 id="hr">Horizontal Rules</h3> 419<p>You can produce a horizontal rule tag (<code><hr /></code>) by placing three or 420more hyphens, asterisks, or underscores on a line by themselves. If you 421wish, you may use spaces between the hyphens or asterisks. Each of the 422following lines will produce a horizontal rule:</p> 423<pre><code>* * * 424 425*** 426 427***** 428 429- - - 430 431--------------------------------------- 432 433_ _ _ 434</code></pre> 435<hr /> 436<h2 id="span">Span Elements</h2> 437<h3 id="link">Links</h3> 438<p>Markdown supports two style of links: <em>inline</em> and <em>reference</em>.</p> 439<p>In both styles, the link text is delimited by [square brackets].</p> 440<p>To create an inline link, use a set of regular parentheses immediately 441after the link text's closing square bracket. Inside the parentheses, 442put the URL where you want the link to point, along with an <em>optional</em> 443title for the link, surrounded in quotes. For example:</p> 444<pre><code>This is [an example](http://example.com/ "Title") inline link. 445 446[This link](http://example.net/) has no title attribute. 447</code></pre> 448<p>Will produce:</p> 449<pre><code><p>This is <a href="http://example.com/" title="Title"> 450an example</a> inline link.</p> 451 452<p><a href="http://example.net/">This link</a> has no 453title attribute.</p> 454</code></pre> 455<p>If you're referring to a local resource on the same server, you can 456use relative paths:</p> 457<pre><code>See my [About](/about/) page for details. 458</code></pre> 459<p>Reference-style links use a second set of square brackets, inside 460which you place a label of your choosing to identify the link:</p> 461<pre><code>This is [an example][id] reference-style link. 462</code></pre> 463<p>You can optionally use a space to separate the sets of brackets:</p> 464<pre><code>This is [an example] [id] reference-style link. 465</code></pre> 466<p>Then, anywhere in the document, you define your link label like this, 467on a line by itself:</p> 468<pre><code>[id]: http://example.com/ "Optional Title Here" 469</code></pre> 470<p>That is:</p> 471<ul> 472<li>Square brackets containing the link identifier (optionally 473indented from the left margin using up to three spaces);</li> 474<li>followed by a colon;</li> 475<li>followed by one or more spaces (or tabs);</li> 476<li>followed by the URL for the link;</li> 477<li>optionally followed by a title attribute for the link, enclosed 478in double or single quotes, or enclosed in parentheses.</li> 479</ul> 480<p>The following three link definitions are equivalent:</p> 481<pre><code>[foo]: http://example.com/ "Optional Title Here" 482[foo]: http://example.com/ 'Optional Title Here' 483[foo]: http://example.com/ (Optional Title Here) 484</code></pre> 485<p><strong>Note:</strong> There is a known bug in Markdown.pl 1.0.1 which prevents 486single quotes from being used to delimit link titles.</p> 487<p>The link URL may, optionally, be surrounded by angle brackets:</p> 488<pre><code>[id]: <http://example.com/> "Optional Title Here" 489</code></pre> 490<p>You can put the title attribute on the next line and use extra spaces 491or tabs for padding, which tends to look better with longer URLs:</p> 492<pre><code>[id]: http://example.com/longish/path/to/resource/here 493 "Optional Title Here" 494</code></pre> 495<p>Link definitions are only used for creating links during Markdown 496processing, and are stripped from your document in the HTML output.</p> 497<p>Link definition names may consist of letters, numbers, spaces, and 498punctuation -- but they are <em>not</em> case sensitive. E.g. these two 499links:</p> 500<pre><code>[link text][a] 501[link text][A] 502</code></pre> 503<p>are equivalent.</p> 504<p>The <em>implicit link name</em> shortcut allows you to omit the name of the 505link, in which case the link text itself is used as the name. 506Just use an empty set of square brackets -- e.g., to link the word 507"Google" to the google.com web site, you could simply write:</p> 508<pre><code>[Google][] 509</code></pre> 510<p>And then define the link:</p> 511<pre><code>[Google]: http://google.com/ 512</code></pre> 513<p>Because link names may contain spaces, this shortcut even works for 514multiple words in the link text:</p> 515<pre><code>Visit [Daring Fireball][] for more information. 516</code></pre> 517<p>And then define the link:</p> 518<pre><code>[Daring Fireball]: http://daringfireball.net/ 519</code></pre> 520<p>Link definitions can be placed anywhere in your Markdown document. I 521tend to put them immediately after each paragraph in which they're 522used, but if you want, you can put them all at the end of your 523document, sort of like footnotes.</p> 524<p>Here's an example of reference links in action:</p> 525<pre><code>I get 10 times more traffic from [Google] [1] than from 526[Yahoo] [2] or [MSN] [3]. 527 528 [1]: http://google.com/ "Google" 529 [2]: http://search.yahoo.com/ "Yahoo Search" 530 [3]: http://search.msn.com/ "MSN Search" 531</code></pre> 532<p>Using the implicit link name shortcut, you could instead write:</p> 533<pre><code>I get 10 times more traffic from [Google][] than from 534[Yahoo][] or [MSN][]. 535 536 [google]: http://google.com/ "Google" 537 [yahoo]: http://search.yahoo.com/ "Yahoo Search" 538 [msn]: http://search.msn.com/ "MSN Search" 539</code></pre> 540<p>Both of the above examples will produce the following HTML output:</p> 541<pre><code><p>I get 10 times more traffic from <a href="http://google.com/" 542title="Google">Google</a> than from 543<a href="http://search.yahoo.com/" title="Yahoo Search">Yahoo</a> 544or <a href="http://search.msn.com/" title="MSN Search">MSN</a>.</p> 545</code></pre> 546<p>For comparison, here is the same paragraph written using 547Markdown's inline link style:</p> 548<pre><code>I get 10 times more traffic from [Google](http://google.com/ "Google") 549than from [Yahoo](http://search.yahoo.com/ "Yahoo Search") or 550[MSN](http://search.msn.com/ "MSN Search"). 551</code></pre> 552<p>The point of reference-style links is not that they're easier to 553write. The point is that with reference-style links, your document 554source is vastly more readable. Compare the above examples: using 555reference-style links, the paragraph itself is only 81 characters 556long; with inline-style links, it's 176 characters; and as raw HTML, 557it's 234 characters. In the raw HTML, there's more markup than there 558is text.</p> 559<p>With Markdown's reference-style links, a source document much more 560closely resembles the final output, as rendered in a browser. By 561allowing you to move the markup-related metadata out of the paragraph, 562you can add links without interrupting the narrative flow of your 563prose.</p> 564<h3 id="em">Emphasis</h3> 565<p>Markdown treats asterisks (<code>*</code>) and underscores (<code>_</code>) as indicators of 566emphasis. Text wrapped with one <code>*</code> or <code>_</code> will be wrapped with an 567HTML <code><em></code> tag; double <code>*</code>'s or <code>_</code>'s will be wrapped with an HTML 568<code><strong></code> tag. E.g., this input:</p> 569<pre><code>*single asterisks* 570 571_single underscores_ 572 573**double asterisks** 574 575__double underscores__ 576</code></pre> 577<p>will produce:</p> 578<pre><code><em>single asterisks</em> 579 580<em>single underscores</em> 581 582<strong>double asterisks</strong> 583 584<strong>double underscores</strong> 585</code></pre> 586<p>You can use whichever style you prefer; the lone restriction is that 587the same character must be used to open and close an emphasis span.</p> 588<p>Emphasis can be used in the middle of a word:</p> 589<pre><code>un*frigging*believable 590</code></pre> 591<p>But if you surround an <code>*</code> or <code>_</code> with spaces, it'll be treated as a 592literal asterisk or underscore.</p> 593<p>To produce a literal asterisk or underscore at a position where it 594would otherwise be used as an emphasis delimiter, you can backslash 595escape it:</p> 596<pre><code>\*this text is surrounded by literal asterisks\* 597</code></pre> 598<h3 id="code">Code</h3> 599<p>To indicate a span of code, wrap it with backtick quotes (<code>`</code>). 600Unlike a pre-formatted code block, a code span indicates code within a 601normal paragraph. For example:</p> 602<pre><code>Use the `printf()` function. 603</code></pre> 604<p>will produce:</p> 605<pre><code><p>Use the <code>printf()</code> function.</p> 606</code></pre> 607<p>To include a literal backtick character within a code span, you can use 608multiple backticks as the opening and closing delimiters:</p> 609<pre><code>``There is a literal backtick (`) here.`` 610</code></pre> 611<p>which will produce this:</p> 612<pre><code><p><code>There is a literal backtick (`) here.</code></p> 613</code></pre> 614<p>The backtick delimiters surrounding a code span may include spaces -- 615one after the opening, one before the closing. This allows you to place 616literal backtick characters at the beginning or end of a code span:</p> 617<pre><code>A single backtick in a code span: `` ` `` 618 619A backtick-delimited string in a code span: `` `foo` `` 620</code></pre> 621<p>will produce:</p> 622<pre><code><p>A single backtick in a code span: <code>`</code></p> 623 624<p>A backtick-delimited string in a code span: <code>`foo`</code></p> 625</code></pre> 626<p>With a code span, ampersands and angle brackets are encoded as HTML 627entities automatically, which makes it easy to include example HTML 628tags. Markdown will turn this:</p> 629<pre><code>Please don't use any `<blink>` tags. 630</code></pre> 631<p>into:</p> 632<pre><code><p>Please don't use any <code>&lt;blink&gt;</code> tags.</p> 633</code></pre> 634<p>You can write this:</p> 635<pre><code>`&#8212;` is the decimal-encoded equivalent of `&mdash;`. 636</code></pre> 637<p>to produce:</p> 638<pre><code><p><code>&amp;#8212;</code> is the decimal-encoded 639equivalent of <code>&amp;mdash;</code>.</p> 640</code></pre> 641<h3 id="img">Images</h3> 642<p>Admittedly, it's fairly difficult to devise a "natural" syntax for 643placing images into a plain text document format.</p> 644<p>Markdown uses an image syntax that is intended to resemble the syntax 645for links, allowing for two styles: <em>inline</em> and <em>reference</em>.</p> 646<p>Inline image syntax looks like this:</p> 647<pre><code> 648 649 650</code></pre> 651<p>That is:</p> 652<ul> 653<li>An exclamation mark: <code>!</code>;</li> 654<li>followed by a set of square brackets, containing the <code>alt</code> 655attribute text for the image;</li> 656<li>followed by a set of parentheses, containing the URL or path to 657the image, and an optional <code>title</code> attribute enclosed in double 658or single quotes.</li> 659</ul> 660<p>Reference-style image syntax looks like this:</p> 661<pre><code>![Alt text][id] 662</code></pre> 663<p>Where "id" is the name of a defined image reference. Image references 664are defined using syntax identical to link references:</p> 665<pre><code>[id]: url/to/image "Optional title attribute" 666</code></pre> 667<p>As of this writing, Markdown has no syntax for specifying the 668dimensions of an image; if this is important to you, you can simply 669use regular HTML <code><img></code> tags.</p> 670<hr /> 671<h2 id="misc">Miscellaneous</h2> 672<h3 id="autolink">Automatic Links</h3> 673<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> 674<pre><code><http://example.com/> 675</code></pre> 676<p>Markdown will turn this into:</p> 677<pre><code><a href="http://example.com/">http://example.com/</a> 678</code></pre> 679<p>Automatic links for email addresses work similarly, except that 680Markdown will also perform a bit of randomized decimal and hex 681entity-encoding to help obscure your address from address-harvesting 682spambots. For example, Markdown will turn this:</p> 683<pre><code><address@example.com> 684</code></pre> 685<p>into something like this:</p> 686<pre><code><a href="&#x6D;&#x61;i&#x6C;&#x74;&#x6F;:&#x61;&#x64;&#x64;&#x72;&#x65; 687&#115;&#115;&#64;&#101;&#120;&#x61;&#109;&#x70;&#x6C;e&#x2E;&#99;&#111; 688&#109;">&#x61;&#x64;&#x64;&#x72;&#x65;&#115;&#115;&#64;&#101;&#120;&#x61; 689&#109;&#x70;&#x6C;e&#x2E;&#99;&#111;&#109;</a> 690</code></pre> 691<p>which will render in a browser as a clickable link to "address@example.com".</p> 692<p>(This sort of entity-encoding trick will indeed fool many, if not 693most, address-harvesting bots, but it definitely won't fool all of 694them. It's better than nothing, but an address published in this way 695will probably eventually start receiving spam.)</p> 696<h3 id="backslash">Backslash Escapes</h3> 697<p>Markdown allows you to use backslash escapes to generate literal 698characters which would otherwise have special meaning in Markdown's 699formatting syntax. For example, if you wanted to surround a word 700with literal asterisks (instead of an HTML <code><em></code> tag), you can use 701backslashes before the asterisks, like this:</p> 702<pre><code>\*literal asterisks\* 703</code></pre> 704<p>Markdown provides backslash escapes for the following characters:</p> 705<pre><code>\ backslash 706` backtick 707* asterisk 708_ underscore 709{} curly braces 710[] square brackets 711() parentheses 712# hash mark 713+ plus sign 714- minus sign (hyphen) 715. dot 716! exclamation mark 717</code></pre> 718
