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| author | Andrey A. Chernov <ache@FreeBSD.org> | 2001-06-11 01:20:40 +0000 |
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| committer | Andrey A. Chernov <ache@FreeBSD.org> | 2001-06-11 01:20:40 +0000 |
| commit | f749b200c1ca3b47c8058de0866f0cf6f69859be (patch) | |
| tree | edd12ebb0622f027051220884a994db606114196 /en_US.ISO_8859-1/books/fdp-primer/sgml-markup/chapter.sgml | |
| parent | e8fc3b162e0f24945430f8fe87bb85ae7f895dfc (diff) | |
| download | doc-f749b200c1ca3b47c8058de0866f0cf6f69859be.tar.gz doc-f749b200c1ca3b47c8058de0866f0cf6f69859be.zip | |
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diff --git a/en_US.ISO_8859-1/books/fdp-primer/sgml-markup/chapter.sgml b/en_US.ISO_8859-1/books/fdp-primer/sgml-markup/chapter.sgml deleted file mode 100644 index d497523e7b..0000000000 --- a/en_US.ISO_8859-1/books/fdp-primer/sgml-markup/chapter.sgml +++ /dev/null @@ -1,2563 +0,0 @@ -<!-- Copyright (c) 1998, 1999 Nik Clayton, All rights reserved. - - Redistribution and use in source (SGML DocBook) and 'compiled' forms - (SGML HTML, PDF, PostScript, RTF and so forth) with or without - modification, are permitted provided that the following conditions - are met: - - 1. Redistributions of source code (SGML DocBook) must retain the above - copyright notice, this list of conditions and the following - disclaimer as the first lines of this file unmodified. - - 2. Redistributions in compiled form (transformed to other DTDs, - converted to PDF, PostScript, RTF and other formats) must reproduce - the above copyright notice, this list of conditions and the - following disclaimer in the documentation and/or other materials - provided with the distribution. - - THIS DOCUMENTATION IS PROVIDED BY NIK CLAYTON "AS IS" AND ANY EXPRESS OR - IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES - OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE - DISCLAIMED. IN NO EVENT SHALL NIK CLAYTON BE LIABLE FOR ANY DIRECT, - INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES - (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR - SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) - HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, - STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN - ANY WAY OUT OF THE USE OF THIS DOCUMENTATION, EVEN IF ADVISED OF THE - POSSIBILITY OF SUCH DAMAGE. - - $FreeBSD: doc/en_US.ISO_8859-1/books/fdp-primer/sgml-markup/chapter.sgml,v 1.19 2001/04/17 16:02:54 nik Exp $ ---> - -<chapter id="sgml-markup"> - <title>SGML Markup</title> - - <para>This chapter describes the three markup languages you will encounter - when you contribute to the FreeBSD documentation project. Each section - describes the markup language, and details the markup that you are likely - to want to use, or that is already in use.</para> - - <para>These markup languages contain a large number of elements, and it can - be confusing sometimes to know which element to use for a particular - situation. This section goes through the elements you are most likely to - need, and gives examples of how you would use them.</para> - - <para>This is <emphasis>not</emphasis> an exhaustive list of elements, since - that would just reiterate the documentation for each language. The aim of - this section is to list those elements more likely to be useful to you. - If you have a question about how best to markup a particular piece of - content, please post it to the FreeBSD Documentation Project mailing list - <email>freebsd-doc@FreeBSD.org</email>.</para> - - <note> - <title>Inline vs. block</title> - - <para>In the remainder of this document, when describing elements, - <emphasis>inline</emphasis> means that the element can occur within a - block element, and does not cause a line break. A - <emphasis>block</emphasis> element, by comparison, will cause a line - break (and other processing) when it is encountered.</para> - </note> - - <sect1> - <title>HTML</title> - - <para>HTML, the HyperText Markup Language, is the markup language of - choice on the World Wide Web. More information can be found at - <URL:<ulink - url="http://www.w3.org/">http://www.w3.org/</ulink>>.</para> - - <para>HTML is used to markup pages on the FreeBSD web site. It should not - (generally) be used to mark up other documention, since DocBook offers a - far richer set of elements to choose from. Consequently, you will - normally only encounter HTML pages if you are writing for the web - site.</para> - - <para>HTML has gone through a number of versions, 1, 2, 3.0, 3.2, and the - latest, 4.0 (available in both <emphasis>strict</emphasis> and - <emphasis>loose</emphasis> variants).</para> - - <para>The HTML DTDs are available from the ports collection in the - <filename>textproc/html</filename> port. They are automatically - installed as part of the <filename>textproc/docproj</filename> - port.</para> - - <sect2> - <title>Formal Public Identifier (FPI)</title> - - <para>There are a number of HTML FPIs, depending upon the version (also - known as the level) of HTML that you want to declare your document to - be compliant with.</para> - - <para>The majority of HTML documents on the FreeBSD web site comply with - the loose version of HTML 4.0.</para> - - <programlisting>PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"</programlisting> - </sect2> - - <sect2> - <title>Sectional elements</title> - - <para>An HTML document is normally split in to two sections. The first - section, called the <emphasis>head</emphasis>, contains - meta-information about the document, such as its title, the name of - the author, the parent document, and so on. The second section, the - <emphasis>body</emphasis>, contains the content that will be displayed - to the user.</para> - - <para>These sections are indicated with <sgmltag>head</sgmltag> and - <sgmltag>body</sgmltag> elements respectively. These elements are - contained within the top-level <sgmltag>html</sgmltag> element.</para> - - <example> - <title>Normal HTML document structure</title> - - <programlisting><html> - <head> - <title><replaceable>The document's title</replaceable></title> - </head> - - <body> - - … - - </body> -</html></programlisting> - </example> - </sect2> - - <sect2> - <title>Block elements</title> - - <sect3> - <title>Headings</title> - - <para>HTML allows you to denote headings in your document, at up to - six different levels.</para> - - <para>The largest and most prominent heading is <sgmltag>h1</sgmltag>, - then <sgmltag>h2</sgmltag>, continuing down to - <sgmltag>h6</sgmltag>.</para> - - <para>The element's content is the text of the heading.</para> - - <example> - <title><sgmltag>h1</sgmltag>, <sgmltag>h2</sgmltag>, etc.</title> - - <para>Use:</para> - - <programlisting><![ CDATA [<h1>First section</h1> - -<!-- Document introduction goes here --> - -<h2>This is the heading for the first section</h2> - -<!-- Content for the first section goes here --> - -<h3>This is the heading for the first sub-section</h3> - -<!-- Content for the first sub-section goes here --> - -<h2>This is the heading for the second section</h2> - -<!-- Content for the second section goes here -->]]></programlisting> - </example> - - <para>Generally, an HTML page should have one first level heading - (<sgmltag>h1</sgmltag>). This can contain many second level - headings (<sgmltag>h2</sgmltag>), which can in turn contain many - third level headings. Each - <sgmltag>h<replaceable>n</replaceable></sgmltag> element should have - the same element, but one further up the hierarchy, preceeding it. - Leaving gaps in the numbering is to be avoided.</para> - - <example> - <title>Bad ordering of - <sgmltag>h<replaceable>n</replaceable></sgmltag> elements</title> - - <para>Use:</para> - - <programlisting><![ CDATA [<h1>First section</h1> - -<!-- Document introduction --> - -<h3>Sub-section</h3> - -<!-- This is bad, <h2> has been left out -->]]></programlisting> - </example> - </sect3> - - <sect3> - <title>Paragraphs</title> - - <para>HTML supports a single paragraph element, - <sgmltag>p</sgmltag>.</para> - - <example> - <title><sgmltag>p</sgmltag></title> - - <para>Use:</para> - - <programlisting><![ CDATA [<p>This is a paragraph. It can contain just about any - other element.</p>]]></programlisting> - </example> - </sect3> - - <sect3> - <title>Block quotations</title> - - <para>A block quotation is an extended quotation from another document - that should not appear within the current paragraph.</para> - - <example> - <title><sgmltag>blockquote</sgmltag></title> - - <para>Use:</para> - - <programlisting><![ CDATA [<p>A small excerpt from the US Constitution:</p> - -<blockquote>We the People of the United States, in Order to form - a more perfect Union, establish Justice, insure domestic - Tranquility, provide for the common defence, promote the general - Welfare, and secure the Blessings of Liberty to ourselves and our - Posterity, do ordain and establish this Constitution for the - United States of America.</blockquote>]]></programlisting> - </example> - </sect3> - - <sect3> - <title>Lists</title> - - <para>You can present the user with three types of lists, ordered, - unordered, and definition.</para> - - <para>Typically, each entry in an ordered list will be numbered, while - each entry in an unordered list will be preceded by a bullet point. - Definition lists are composed of two sections for each entry. The - first section is the term being defined, and the second section is - the definition of the term.</para> - - <para>Ordered lists are indicated by the <sgmltag>ol</sgmltag> - element, unordered lists by the <sgmltag>ul</sgmltag> element, and - definition lists by the <sgmltag>dl</sgmltag> element.</para> - - <para>Ordered and unordered lists contain listitems, indicated by the - <sgmltag>li</sgmltag> element. A listitem can contain textual - content, or it may be further wrapped in one or more - <sgmltag>p</sgmltag> elements.</para> - - <para>Definition lists contain definition terms - (<sgmltag>dt</sgmltag>) and definition descriptions - (<sgmltag>dd</sgmltag>). A definition term can only contain inline - elements. A definition description can contain other block - elements.</para> - - <example> - <title><sgmltag>ul</sgmltag> and <sgmltag>ol</sgmltag></title> - - <para>Use:</para> - - <programlisting><![ CDATA [<p>An unordered list. Listitems will probably be - preceeded by bullets.</p> - -<ul> - <li>First item</li> - - <li>Second item</li> - - <li>Third item</li> -</ul> - -<p>An ordered list, with list items consisting of multiple - paragraphs. Each item (note: not each paragraph) will be - numbered.</p> - -<ol> - <li><p>This is the first item. It only has one paragraph.</p></li> - - <li><p>This is the first paragraph of the second item.</p> - - <p>This is the second paragraph of the second item.</p></li> - - <li><p>This is the first and only paragraph of the third - item.</p></li> -</ol>]]></programlisting> - </example> - - <example> - <title>Definition lists with <sgmltag>dl</sgmltag></title> - - <para>Use:</para> - - <programlisting><![ CDATA [<dl> - <dt>Term 1</dt> - - <dd><p>Paragraph 1 of definition 1.</p></dd> - - <p>Paragraph 2 of definition 1.</p></dd> - - <dt>Term 2</dt> - - <dd><p>Paragraph 1 of definition 2.</p></dd> - - <dt>Term 3</dt> - - <dd>Paragraph 1 of definition 3. Note that the <p> - element is not required in the single paragraph case.</dd> -</dl>]]></programlisting> - </example> - </sect3> - - <sect3> - <title>Pre-formatted text</title> - - <para>You can indicate that text should be shown to the user exactly - as it is in the file. Typically, this means that the text is shown - in a fixed font, multiple spaces are not merged in to one, and line - breaks in the text are significant.</para> - - <para>In order to do this, wrap the content in the - <sgmltag>pre</sgmltag> element.</para> - - <example> - <title><sgmltag>pre</sgmltag></title> - - <para>You could use <sgmltag>pre</sgmltag> to mark up an e-mail - message;</para> - - <programlisting><![ CDATA [<pre> From: nik@FreeBSD.org - To: freebsd-doc@FreeBSD.org - Subject: New documentation available - - There's a new copy of my primer for contributers to the FreeBSD - Documentation Project available at - - <URL:http://people.FreeBSD.org/~nik/primer/index.html> - - Comments appreciated. - - N</pre>]]></programlisting> - </example> - </sect3> - - <sect3> - <title>Tables</title> - - <note> - <para>Most text-mode browsers (such as Lynx) do not render tables - particularly effectively. If you are relying on the tabular - display of your content, you should consider using alternative - markup to prevent confusion.</para> - </note> - - <para>Mark up tabular information using the <sgmltag>table</sgmltag> - element. A table consists of one or more table rows - (<sgmltag>tr</sgmltag>), each containing one or more cells of table - data (<sgmltag>td</sgmltag>). Each cell can contain other block - elements, such as paragraphs or lists. It can also contain another - table (this nesting can repeat indefinitely). If the cell only - contains one paragraph then you do not need to include the - <sgmltag>p</sgmltag> element.</para> - - <example> - <title>Simple use of <sgmltag>table</sgmltag></title> - - <para>Use:</para> - - <programlisting><![ CDATA [<p>This is a simple 2x2 table.</p> - -<table> - <tr> - <td>Top left cell</td> - - <td>Top right cell</td> - </tr> - - <tr> - <td>Bottom left cell</td> - - <td>Bottom right cell</td> - </tr> -</table>]]></programlisting></example> - - <para>A cell can span multiple rows and columns. To indicate this, - add the <literal>rowspan</literal> and/or <literal>colspan</literal> - attributes, with values indicating the number of rows of columns - that should be spanned.</para> - - <example> - <title>Using <literal>rowspan</literal></title> - - <para>Use:</para> - - <programlisting><![ CDATA [<p>One tall thin cell on the left, two short cells next to - it on the right.</p> - -<table> - <tr> - <td rowspan="2">Long and thin</td> - </tr> - - <tr> - <td>Top cell</td> - - <td>Bottom cell</td> - </tr> -</table>]]></programlisting> - </example> - - <example> - <title>Using <literal>colspan</literal></title> - - <para>Use:</para> - - <programlisting><![ CDATA [<p>One long cell on top, two short cells below it.</p> - -<table> - <tr> - <td colspan="2">Top cell</td> - </tr> - - <tr> - <td>Bottom left cell</td> - - <td>Bottom right cell</td> - </tr> -</table>]]></programlisting> - </example> - - <example> - <title>Using <literal>rowspan</literal> and - <literal>colspan</literal> together</title> - - <para>Use:</para> - - <programlisting><![ CDATA [<p>On a 3x3 grid, the top left block is a 2x2 set of - cells merged in to one. The other cells are normal.</p> - -<table> - <tr> - <td colspan="2" rowspan="2">Top left large cell</td> - - <td>Top right cell</td> - </tr> - - <tr> - <!-- Because the large cell on the left merges in to - this row, the first <td> will occur on its - right --> - - <td>Middle right cell</td> - </tr> - - <tr> - <td>Bottom left cell</td> - - <td>Bottom middle cell</td> - - <td>Bottom right cell</td> - </tr> -</table>]]></programlisting> - </example> - </sect3> - </sect2> - - <sect2> - <title>In-line elements</title> - - <sect3> - <title>Emphasising information</title> - - <para>You have two levels of emphasis available in HTML, - <sgmltag>em</sgmltag> and <sgmltag>strong</sgmltag>. - <sgmltag>em</sgmltag> is for a normal level of emphasis and - <sgmltag>strong</sgmltag> indicates stronger emphasis.</para> - - <para>Typically, <sgmltag>em</sgmltag> is rendered in italic and - <sgmltag>strong</sgmltag> is rendered in bold. This is not always - the case, however, and you should not rely on it.</para> - - <example> - <title><sgmltag>em</sgmltag> and <sgmltag>strong</sgmltag></title> - - <para>Use:</para> - - <programlisting><![ CDATA [<p><em>This</em> has been emphasised, while - <strong>this</strong> has been strongly emphasised.</p>]]></programlisting> - </example> - </sect3> - - <sect3> - <title>Bold and italics</title> - - <para>Because HTML includes presentational markup, you can also - indicate that particular content should be rendered in bold or - italic. The elements are <sgmltag>b</sgmltag> and - <sgmltag>i</sgmltag> respectively.</para> - - <example> - <title><sgmltag>b</sgmltag> and <sgmltag>i</sgmltag></title> - - <programlisting><![ CDATA [<p><b>This</b> is in bold, while <i>this</i> is - in italics.</p>]]></programlisting> - </example> - </sect3> - - <sect3> - <title>Indicating fixed pitch text</title> - - <para>If you have content that should be rendered in a fixed pitch - (typewriter) typeface, use <sgmltag>tt</sgmltag> (for - “teletype”).</para> - - <example> - <title><sgmltag>tt</sgmltag></title> - - <para>Use:</para> - - <programlisting><![ CDATA [<p>This document was originally written by - Nik Clayton, who can be reached by e-mail as - <tt>nik@FreeBSD.org</tt>.</p>]]></programlisting> - </example> - </sect3> - - <sect3> - <title>Content size</title> - - <para>You can indicate that content should be shown in a larger or - smaller font. There are three ways of doing this.</para> - - <orderedlist> - <listitem> - <para>Use <sgmltag>big</sgmltag> and <sgmltag>small</sgmltag> - around the content you wish to change size. These tags can be - nested, so <literal><big><big>This is much - bigger</big></big></literal> is possible.</para> - </listitem> - - <listitem> - <para>Use <sgmltag>font</sgmltag> with the <literal>size</literal> - attribute set to <literal>+1</literal> or <literal>-1</literal> - respectively. This has the same effect as using - <sgmltag>big</sgmltag> or <sgmltag>small</sgmltag>. However, - the use of this approach is deprecated.</para> - </listitem> - - <listitem> - <para>Use <sgmltag>font</sgmltag> with the <literal>size</literal> - attribute set to a number between 1 and 7. The default font size - is <literal>3</literal>. This approach is deprecated.</para> - </listitem> - </orderedlist> - - <example> - <title><sgmltag>big</sgmltag>, <sgmltag>small</sgmltag>, and - <sgmltag>font</sgmltag></title> - - <para>The following fragments all do the same thing.</para> - - <programlisting><![ CDATA [<p>This text is <small>slightly smaller</small>. But - this text is <big>slightly bigger</big>.</p> - -<p>This text is <font size="-1">slightly smaller</font>. But - this text is <font size="+1">slightly bigger</font.</p> - -<p>This text is <font size="2">slightly smaller</font>. But - this text is <font size="4">slightly bigger</font>.</p>]]></programlisting> - </example> - </sect3> - </sect2> - - <sect2> - <title>Links</title> - - <note> - <para>Links are also in-line elements.</para> - </note> - - <sect3> - <title>Linking to other documents on the WWW</title> - - <para>In order to include a link to another document on the WWW you - must know the URL of the document you want to link to.</para> - - <para>The link is indicated with <sgmltag>a</sgmltag>, and the - <literal>href</literal> attribute contains the URL of the target - document. The content of the element becomes the link, and is - normally indicated to the user in some way (underlining, change of - colour, different mouse cursor when over the link, and so - on).</para> - - <example> - <title>Using <literal><a href="..."></literal></title> - - <para>Use:</para> - - <programlisting><![ CDATA [<p>More information is available at the - <a href="http://www.FreeBSD.org/">FreeBSD web site</a>.</p>]]></programlisting> - </example> - - <para>These links will take the user to the top of the chosen - document.</para> - </sect3> - - <sect3> - <title>Linking to other parts of documents</title> - - <para>Linking to a point within another document (or within the same - document) requires that the document author include anchors that you - can link to.</para> - - <para>Anchors are indicated with <sgmltag>a</sgmltag> and the - <literal>name</literal> attribute instead of - <literal>href</literal>.</para> - - <example> - <title>Using <literal><a name="..."></literal></title> - - <para>Use:</para> - - <programlisting><![ CDATA [<p><a name="para1">This</a> paragraph can be referenced - in other links with the name <tt>para1</tt>.</p>]]></programlisting> - </example> - - <para>To link to a named part of a document, write a normal link to - that document, but include the name of the anchor after a - <literal>#</literal> symbol.</para> - - <example> - <title>Linking to a named part of another document</title> - - <para>Assume that the <literal>para1</literal> example resides in a - document called <filename>foo.html</filename>.</para> - - <programlisting><![ CDATA [<p>More information can be found in the - <a href="foo.html#para1">first paragraph</a> of - <tt>foo.html</tt>.</p>]]></programlisting> - </example> - - <para>If you are linking to a named anchor within the same document - then you can omit the document's URL, and just include the name of - the anchor (with the preceeding <literal>#</literal>).</para> - - <example> - <title>Linking to a named part of the same document</title> - - <para>Assume that the <literal>para1</literal> example resides in - this document</para> - - <programlisting><![ CDATA [<p>More information can be found in the - <a href="#para1">first paragraph</a> of this - document.</p>]]></programlisting> - </example> - </sect3> - </sect2> - </sect1> - - <sect1> - <title>DocBook</title> - - <para>DocBook was designed by the <ulink - url="http://www.oreilly.com/davenport/">Davenport Group</ulink> to be - a DTD for writing technical documentation. As such, and unlike LinuxDoc - and HTML, DocBook is very heavily oriented towards markup that - describes <emphasis>what</emphasis> something is, rather than describing - <emphasis>how</emphasis> it should be presented.</para> - - <note> - <title><literal>formal</literal> vs. <literal>informal</literal></title> - - <para>Some elements may exist in two forms, <emphasis>formal</emphasis> - and <emphasis>informal</emphasis>. Typically, the formal version of - the element will consist of a title followed by the information - version of the element. The informal version will not have a - title.</para> - </note> - - <para>The DocBook DTD is available from the ports collection in the - <filename>textproc/docbook</filename> port. It is automatically - installed as part of the <filename>textproc/docproj</filename> - port.</para> - - <sect2> - <title>FreeBSD extensions</title> - - <para>The FreeBSD Documentation Project has extended the DocBook DTD by - adding some new elements. These elements serve to make some of the - markup more precise.</para> - - <para>Where a FreeBSD specific element is listed below it is clearly - marked.</para> - - <para>Throughout the rest of this document, the term - “DocBook” is used to mean the FreeBSD extended DocBook - DTD.</para> - - <note> - <para>There is nothing about these extensions that is FreeBSD - specific, it was just felt that they were useful enhancements for - this particular project. Should anyone from any of the other *nix - camps (NetBSD, OpenBSD, Linux, …) be interested in - collaborating on a standard DocBook extension set, please get in - touch with Nik Clayton <email>nik@FreeBSD.org</email>.</para> - </note> - - <para>The FreeBSD extensions are not (currently) in the ports - collection. They are stored in the FreeBSD CVS tree, as <ulink - url="http://www.freebsd.org/cgi/cvsweb.cgi/doc/share/sgml/freebsd.dtd">doc/share/sgml/freebsd.dtd</ulink>.</para> - </sect2> - - <sect2> - <title>Formal Public Identifier (FPI)</title> - - <para>In compliance with the DocBook guidelines for writing FPIs for - DocBook customisations, the FPI for the FreeBSD extended DocBook DTD - is;</para> - - <programlisting>PUBLIC "-//FreeBSD//DTD DocBook V4.1-Based Extension//EN"</programlisting> - </sect2> - - <sect2> - <title>Document structure</title> - - <para>DocBook allows you to structure your documentation in several - ways. In the FreeBSD Documentation Project we are using two primary - types of DocBook document: the book and the article.</para> - - <para>A book is organised into <sgmltag>chapter</sgmltag>s. This is a - mandatory requirement. There may be <sgmltag>part</sgmltag>s between - the book and the chapter to provide another layer of organisation. - The Handbook is arranged in this way.</para> - - <para>A chapter may (or may not) contain one or more sections. These - are indicated with the <sgmltag>sect1</sgmltag> element. If a section - contains another section then use the <sgmltag>sect2</sgmltag> - element, and so on, up to <sgmltag>sect5</sgmltag>.</para> - - <para>Chapters and sections contain the remainder of the content.</para> - - <para>An article is simpler than a book, and does not use chapters. - Instead, the content of an article is organised into one or more - sections, using the same <sgmltag>sect1</sgmltag> (and - <sgmltag>sect2</sgmltag> and so on) elements that are used in - books.</para> - - <para>Obviously, you should consider the nature of the documentation you - are writing in order to decide whether it is best marked up as a book - or an article. Articles are well suited to information that does not - need to be broken down into several chapters, and that is, relatively - speaking, quite short, at up to 20-25 pages of content. Books are - best suited to information that can be broken up into several - chapters, possibly with appendices and similar content as well.</para> - - <para>The <ulink url="http://www.FreeBSD.org/tutorials/">FreeBSD - tutorials</ulink> are all marked up as articles, while this - document, the <ulink url="http://www.FreeBSD.org/FAQ/">FreeBSD - FAQ</ulink>, and the <ulink - url="http://www.FreeBSD.org/handbook/">FreeBSD Handbook</ulink> are - all marked up as books.</para> - - <sect3> - <title>Starting a book</title> - - <para>The content of the book is contained within the - <sgmltag>book</sgmltag> element. As well as containing structural - markup, this element can contain elements that include additional - information about the book. This is either meta-information, used - for reference purposes, or additional content used to produce a - title page.</para> - - <para>This additional information should be contained within - <sgmltag>bookinfo</sgmltag>.</para> - - <example> - <title>Boilerplate <sgmltag>book</sgmltag> with - <sgmltag>bookinfo</sgmltag></title> - - <!-- Can't put this in a marked section because of the - replaceable elements --> - <programlisting><book> - <bookinfo> - <title><replaceable>Your title here</replaceable></title> - - <author> - <firstname><replaceable>Your first name</replaceable></firstname> - <surname><replaceable>Your surname</replaceable></surname> - <affiliation> - <address><email><replaceable>Your e-mail address</replaceable></email></address> - </affiliation> - </author> - - <copyright> - <year><replaceable>1998</replaceable></year> - <holder role="mailto:<replaceable>your e-mail address</replaceable>"><replaceable>Your name</replaceable></holder> - </copyright> - - <pubdate role="rcs">$Date$</pubdate> - - <releaseinfo>$Id$</releaseinfo> - - <abstract> - <para><replaceable>Include an abstract of the book's contents here.</replaceable></para> - </abstract> - </bookinfo> - - … - -</book></programlisting> - </example> - </sect3> - - <sect3> - <title>Starting an article</title> - - <para>The content of the article is contained within the - <sgmltag>article</sgmltag> element. As well as containing - structural markup, this element can contain elements that include - additional information about the article. This is either - meta-information, used for reference purposes, or additional content - used to produce a title page.</para> - - <para>This additional information should be contained within - <sgmltag>articleinfo</sgmltag>.</para> - - <example> - <title>Boilerplate <sgmltag>article</sgmltag> with - <sgmltag>articleinfo</sgmltag></title> - - <!-- Can't put this in a marked section because of the - replaceable elements --> - <programlisting><article> - <articleinfo> - <title><replaceable>Your title here</replaceable></title> - - <author> - <firstname><replaceable>Your first name</replaceable></firstname> - <surname><replaceable>Your surname</replaceable></surname> - <affiliation> - <address><email><replaceable>Your e-mail address</replaceable></email></address> - </affiliation> - </author> - - <copyright> - <year><replaceable>1998</replaceable></year> - <holder role="mailto:<replaceable>your e-mail address</replaceable>"><replaceable>Your name</replaceable></holder> - </copyright> - - <pubdate role="rcs">$Date$</pubdate> - - <releaseinfo>$Id$</releaseinfo> - - <abstract> - <para><replaceable>Include an abstract of the article's contents here.</replaceable></para> - </abstract> - </articleinfo> - - … - -</article></programlisting> - </example> - </sect3> - <sect3> - <title>Indicating chapters</title> - - <para>Use <sgmltag>chapter</sgmltag> to mark up your chapters. Each - chapter has a mandatory <sgmltag>title</sgmltag>. Articles do not - contain chapters, they are reserved for books.</para> - - <example> - <title>A simple chapter</title> - - <programlisting><![ CDATA [<chapter> - <title>The chapter's title</title> - - ... -</chapter>]]></programlisting> - </example> - - <para>A chapter cannot be empty; it must contain elements in addition - to <sgmltag>title</sgmltag>. If you need to include an empty - chapter then just use an empty paragraph.</para> - - <example> - <title>Empty chapters</title> - - <programlisting><![ CDATA [<chapter> - <title>This is an empty chapter</title> - - <para></para> -</chapter>]]></programlisting> - </example> - </sect3> - - <sect3> - <title>Sections below chapters</title> - - <para>In books, chapters may (but do not need to) be broken up into - sections, subsections, and so on. In articles, sections are the - main structural element, and each article must contain at least one - section. Use the - <sgmltag>sect<replaceable>n</replaceable></sgmltag> element. The - <replaceable>n</replaceable> indicates the section number, which - identifies the section level.</para> - - <para>The first <sgmltag>sect<replaceable>n</replaceable></sgmltag> is - <sgmltag>sect1</sgmltag>. You can have one or more of these in a - chapter. They can contain one or more <sgmltag>sect2</sgmltag> - elements, and so on, down to <sgmltag>sect5</sgmltag>.</para> - - <example> - <title>Sections in chapters</title> - - <programlisting><![ RCDATA [<chapter> - <title>A sample chapter</title> - - <para>Some text in the chapter.</para> - - <sect1> - <title>First section (1.1)</title> - - … - </sect1> - - <sect1> - <title>Second section (1.2)</title> - - <sect2> - <title>First sub-section (1.2.1)</title> - - <sect3> - <title>First sub-sub-section (1.2.1.1)</title> - - … - </sect3> - </sect2> - - <sect2> - <title>Second sub-section (1.2.2)</title> - - … - </sect2> - </sect1> -</chapter>]]></programlisting> - </example> - - <note> - <para>This example includes section numbers in the section titles. - You should not do this in your documents. Adding the section - numbers is carried out the by the stylesheets (of which more - later), and you do not need to manage them yourself.</para> - </note> - </sect3> - - <sect3> - <title>Subdividing using <sgmltag>part</sgmltag>s</title> - - <para>You can introduce another layer of organisation between - <sgmltag>book</sgmltag> and <sgmltag>chapter</sgmltag> with one or - more <sgmltag>part</sgmltag>s. This cannot be done in an - <sgmltag>article</sgmltag>.</para> - - <programlisting><![ CDATA [<part> - <title>Introduction</title> - - <chapter> - <title>Overview</title> - - ... - </chapter> - - <chapter> - <title>What is FreeBSD?</title> - - ... - </chapter> - - <chapter> - <title>History</title> - - ... - </chapter> -</part>]]></programlisting> - </sect3> - </sect2> - - <sect2> - <title>Block elements</title> - - <sect3> - <title>Paragraphs</title> - - <para>DocBook supports three types of paragraphs: - <sgmltag>formalpara</sgmltag>, <sgmltag>para</sgmltag>, and - <sgmltag>simpara</sgmltag>.</para> - - <para>Most of the time you will only need to use - <sgmltag>para</sgmltag>. <sgmltag>formalpara</sgmltag> includes a - <sgmltag>title</sgmltag> element, and <sgmltag>simpara</sgmltag> - disallows some elements from within <sgmltag>para</sgmltag>. Stick - with <sgmltag>para</sgmltag>.</para> - - <example> - <title><sgmltag>para</sgmltag></title> - - <para>Use:</para> - - <programlisting><![ CDATA [<para>This is a paragraph. It can contain just about any - other element.</para> ]]></programlisting> - - <para>Appearance:</para> - - <para>This is a paragraph. It can contain just about any other - element.</para> - </example> - </sect3> - - <sect3> - <title>Block quotations</title> - - <para>A block quotation is an extended quotation from another document - that should not appear within the current paragraph. You will - probably only need it infrequently.</para> - - <para>Blockquotes can optionally contain a title and an attribution - (or they can be left untitled and unattributed).</para> - - <example> - <title><sgmltag>blockquote</sgmltag></title> - - <para>Use:</para> - - <programlisting><![ CDATA [<para>A small excerpt from the US Constitution;</para> - -<blockquote> - <title>Preamble to the Constitution of the United States</title> - - <attribution>Copied from a web site somewhere</attribution> - - <para>We the People of the United States, in Order to form a more perfect - Union, establish Justice, insure domestic Tranquility, provide for the - common defence, promote the general Welfare, and secure the Blessings - of Liberty to ourselves and our Posterity, do ordain and establish this - Constitution for the United States of America.</para> -</blockquote>]]></programlisting> - - <para>Appearance:</para> - - <blockquote> - <title>Preamble to the Constitution of the United States</title> - - <attribution>Copied from a web site somewhere</attribution> - - <para>We the People of the United States, in Order to form a more - perfect Union, establish Justice, insure domestic Tranquility, - provide for the common defence, promote the general Welfare, and - secure the Blessings of Liberty to ourselves and our Posterity, - do ordain and establish this Constitution for the United States - of America.</para> - </blockquote> - </example> - </sect3> - - <sect3> - <title>Tips, notes, warnings, cautions, important information and - sidebars.</title> - - <para>You may need to include extra information separate from the - main body of the text. Typically this is “meta” - information that the user should be aware of.</para> - - <para>Depending on the nature of the information, one of - <sgmltag>tip</sgmltag>, <sgmltag>note</sgmltag>, - <sgmltag>warning</sgmltag>, <sgmltag>caution</sgmltag>, and - <sgmltag>important</sgmltag> should be used. Alternatively, if the - information is related to the main text but is not one of the above, - use <sgmltag>sidebar</sgmltag>.</para> - - <para>The circumstances in which to choose one of these elements over - another is unclear. The DocBook documentation suggests;</para> - - <itemizedlist> - <listitem> - <para>A Note is for information that should be heeded by all - readers.</para> - </listitem> - - <listitem> - <para>An Important element is a variation on Note.</para> - </listitem> - - <listitem> - <para>A Caution is for information regarding possible data loss - or software damage.</para> - </listitem> - - <listitem> - <para>A Warning is for information regarding possible hardware - damage or injury to life or limb.</para> - </listitem> - </itemizedlist> - - <example> - <title><sgmltag>warning</sgmltag></title> - - <para>Use:</para> - - <programlisting><![ CDATA [<warning> - <para>Installing FreeBSD may make you want to delete Windows from your - harddisk.</para> -</warning>]]></programlisting> - </example> - - <!-- Need to do this outside of the example --> - <warning> - <para>Installing FreeBSD may make you want to delete Windows from - your harddisk.</para> - </warning> - </sect3> - - <sect3> - <title>Lists and procedures</title> - - <para>You will often need to list pieces of information to the user, - or present them with a number of steps that must be carried out in - order to accomplish a particular goal.</para> - - <para>In order to do this, use <sgmltag>itemizedlist</sgmltag>, - <sgmltag>orderedlist</sgmltag>, or - <sgmltag>procedure</sgmltag><footnote><para>There are other types of - list element in DocBook, but we're not concerned with those at - the moment.</para> - </footnote> - </para> - - <para><sgmltag>itemizedlist</sgmltag> and - <sgmltag>orderedlist</sgmltag> are similar to their counterparts in - HTML, <sgmltag>ul</sgmltag> and <sgmltag>ol</sgmltag>. Each one - consists of one or more <sgmltag>listitem</sgmltag> elements, and - each <sgmltag>listitem</sgmltag> contains one or more block - elements. The <sgmltag>listitem</sgmltag> elements are analagous to - HTML's <sgmltag>li</sgmltag> tags. However, unlike HTML, they are - required.</para> - - <para><sgmltag>procedure</sgmltag> is slightly different. It consists - of <sgmltag>step</sgmltag>s, which may in turn consists of more - <sgmltag>step</sgmltag>s or <sgmltag>substep</sgmltag>s. Each - <sgmltag>step</sgmltag> contains block elements.</para> - - <example> - <title><sgmltag>itemizedlist</sgmltag>, - <sgmltag>orderedlist</sgmltag>, and - <sgmltag>procedure</sgmltag></title> - - <para>Use:</para> - - <programlisting><![ CDATA [<itemizedlist> - <listitem> - <para>This is the first itemized item.</para> - </listitem> - - <listitem> - <para>This is the second itemized item.</para> - </listitem> -</itemizedlist> - -<orderedlist> - <listitem> - <para>This is the first ordered item.</para> - </listitem> - - <listitem> - <para>This is the second ordered item.</para> - </listitem> -</orderedlist> - -<procedure> - <step> - <para>Do this.</para> - </step> - - <step> - <para>Then do this.</para> - </step> - - <step> - <para>And now do this.</para> - </step> -</procedure>]]></programlisting> - - <para>Appearance:</para> - - <itemizedlist> - <listitem> - <para>This is the first itemized item.</para> - </listitem> - - <listitem> - <para>This is the second itemized item.</para> - </listitem> - </itemizedlist> - - <orderedlist> - <listitem> - <para>This is the first ordered item.</para> - </listitem> - - <listitem> - <para>This is the second ordered item.</para> - </listitem> - </orderedlist> - </example> - - <!-- Can't have <procedure> inside <example>, so this is a cheat --> - - <procedure> - <step> - <para>Do this.</para> - </step> - - <step> - <para>Then do this.</para> - </step> - - <step> - <para>And now do this.</para> - </step> - </procedure> - </sect3> - - <sect3> - <title>Showing file samples</title> - - <para>If you want to show a fragment of a file (or perhaps a complete - file) to the user, wrap it in the <sgmltag>programlisting</sgmltag> - element.</para> - - <para>White space and line breaks within - <sgmltag>programlisting</sgmltag> <emphasis>are</emphasis> - significant. In particular, this means that the opening tag should - appear on the same line as the first line of the output, and the - closing tag should appear on the same line as the last line of the - output, otherwise spurious blank lines may be included.</para> - - <example> - <title><sgmltag>programlisting</sgmltag></title> - - <para>Use:</para> - - <programlisting><![ CDATA[<para>When you have finished, your program should look like - this;</para> - -<programlisting>#include <stdio.h> - -int -main(void) -{ - printf("hello, world\n"); -}</programlisting>]]></programlisting> - - <para>Notice how the angle brackets in the - <literal>#include</literal> line need to be referenced by their - entities instead of being included literally.</para> - - <para>Appearance:</para> - - <para>When you have finished, your program should look like - this;</para> - - <programlisting>#include <stdio.h> - -int -main(void) -{ - printf("hello, world\n"); -}</programlisting> - </example> - </sect3> - - <sect3> - <title>Callouts</title> - - <para>A callout is a mechanism for referring back to an earlier piece - of text or specific position within an earlier example without - linking to it within the text.</para> - - <para>To do this, mark areas of interest in your example - (<sgmltag>programlisting</sgmltag>, - <sgmltag>literallayout</sgmltag>, or whatever) with the - <sgmltag>co</sgmltag> element. Each element must have a unique - <literal>id</literal> assigned to it. After the example include a - <sgmltag>calloutlist</sgmltag> that refers back to the example and - provides additional commentary.</para> - - <example> - <title><sgmltag>co</sgmltag> and - <sgmltag>calloutlist</sgmltag></title> - - <programlisting><![ CDATA[<para>When you have finished, your program should look like - this;</para> - -<programlisting>#include <stdio.h> <co id="co-ex-include"> - -int <co id="co-ex-return"> -main(void) -{ - printf("hello, world\n"); <co id="co-ex-printf"> -}</programlisting> - -<calloutlist> - <callout arearefs="co-ex-include"> - <para>Includes the standard IO header file.</para> - </callout> - - <callout arearefs="co-ex-return"> - <para>Specifies that <function>main()</function> returns an - int.</para> - </callout> - - <callout arearefs="co-ex-printf"> - <para>The <function>printf()</function> call that writes - <literal>hello, world</literal> to standard output.</para> - </callout> -</calloutlist>]]></programlisting> - - <para>Appearance:</para> - - <para>When you have finished, your program should look like - this;</para> - - <programlisting>#include <stdio.h> <co id="co-ex-include"> - -int <co id="co-ex-return"> -main(void) -{ - printf("hello, world\n"); <co id="co-ex-printf"> -}</programlisting> - - <calloutlist> - <callout arearefs="co-ex-include"> - <para>Includes the standard IO header file.</para> - </callout> - - <callout arearefs="co-ex-return"> - <para>Specifies that <function>main()</function> returns an - int.</para> - </callout> - - <callout arearefs="co-ex-printf"> - <para>The <function>printf()</function> call that writes - <literal>hello, world</literal> to standard output.</para> - </callout> - </calloutlist> - </example> - </sect3> - - <sect3> - <title>Tables</title> - - <para>Unlike HTML, you do not need to use tables for layout purposes, - as the stylesheet handles those issues for you. Instead, just use - tables for marking up tabular data.</para> - - <para>In general terms (and see the DocBook documentation for more - detail) a table (which can be either formal or informal) consists of - a <sgmltag>table</sgmltag> element. This contains at least one - <sgmltag>tgroup</sgmltag> element, which specifies (as an attribute) - the number of columns in this table group. Within the tablegroup - you can then have one <sgmltag>thead</sgmltag> element, which - contains elements for the table headings (column headings), and one - <sgmltag>tbody</sgmltag> which contains the body of the - table.</para> - - <para>Both <sgmltag>tgroup</sgmltag> and <sgmltag>thead</sgmltag> - contain <sgmltag>row</sgmltag> elements, which in turn contain - <sgmltag>entry</sgmltag> elements. Each <sgmltag>entry</sgmltag> - element specifies one cell in the table.</para> - - <example> - <title><sgmltag>informaltable</sgmltag></title> - - <para>Use:</para> - - <programlisting><![ CDATA [<informaltable> - <tgroup cols="2"> - <thead> - <row> - <entry>This is column head 1</entry> - <entry>This is column head 2</entry> - </row> - </thead> - - <tbody> - <row> - <entry>Row 1, column 1</entry> - <entry>Row 1, column 2</entry> - </row> - - <row> - <entry>Row 2, column 1</entry> - <entry>Row 2, column 2</entry> - </row> - </tbody> - </tgroup> -</informaltable>]]></programlisting> - - <para>Appearance:</para> - - <informaltable> - <tgroup cols="2"> - <thead> - <row> - <entry>This is column head 1</entry> - <entry>This is column head 2</entry> - </row> - </thead> - - <tbody> - <row> - <entry>Row 1, column 1</entry> - <entry>Row 1, column 2</entry> - </row> - - <row> - <entry>Row 2, column 1</entry> - <entry>Row 2, column 2</entry> - </row> - </tbody> - </tgroup> - </informaltable> - </example> - - <para>If you don't want a border around the table the - <literal>frame</literal> attribute can be added to the - <sgmltag>informaltable</sgmltag> element with a value of - <literal>none</literal> (i.e., <literal><informaltable - frame="none"></literal>).</para> - - <example> - <title>Tables where <literal>frame="none"</literal></title> - - <para>Appearance:</para> - - <informaltable frame="none"> - <tgroup cols="2"> - <thead> - <row> - <entry>This is column head 1</entry> - <entry>This is column head 2</entry> - </row> - </thead> - - <tbody> - <row> - <entry>Row 1, column 1</entry> - <entry>Row 1, column 2</entry> - </row> - - <row> - <entry>Row 2, column 1</entry> - <entry>Row 2, column 2</entry> - </row> - </tbody> - </tgroup> - </informaltable> - </example> - </sect3> - - <sect3> - <title>Examples for the user to follow</title> - - <para>A lot of the time you need to show examples for the user to - follow. Typically, these will consist of dialogs with the computer; - the user types in a command, the user gets a response back, they - type in another command, and so on.</para> - - <para>A number of distinct elements and entities come in to play - here.</para> - - <variablelist> - <varlistentry> - <term><sgmltag>screen</sgmltag></term> - - <listitem> - <para>Everything the user sees in this example will be on the - computer screen, so the next element is - <sgmltag>screen</sgmltag>.</para> - - <para>Within <sgmltag>screen</sgmltag>, white space is - significant.</para> - </listitem> - </varlistentry> - - <varlistentry> - <term><sgmltag>prompt</sgmltag>, - <literal>&prompt.root;</literal> and - <literal>&prompt.user;</literal></term> - - <listitem> - <para>Some of the things the user will be seeing on the screen - are prompts from the computer (either from the OS, command - shell, or application. These should be marked up using - <sgmltag>prompt</sgmltag>.</para> - - <para>As a special case, the two shell prompts for the normal - user and the root user have been provided as entities. Every - time you want to indicate the user is at a shell prompt, use - one of <literal>&prompt.root;</literal> and - <literal>&prompt.user;</literal> as necessary. They do - not need to be inside <sgmltag>prompt</sgmltag>.</para> - - <note> - <para><literal>&prompt.root;</literal> and - <literal>&prompt.user;</literal> are FreeBSD - extensions to DocBook, and are not part of the original - DTD.</para> - </note> - </listitem> - </varlistentry> - - <varlistentry> - <term><sgmltag>userinput</sgmltag></term> - - <listitem> - <para>When displaying text that the user should type in, wrap it - in <sgmltag>userinput</sgmltag> tags. It will probably be - displayed differently to the user.</para> - </listitem> - </varlistentry> - </variablelist> - - <example> - <title><sgmltag>screen</sgmltag>, <sgmltag>prompt</sgmltag>, and - <sgmltag>userinput</sgmltag></title> - - <para>Use:</para> - - <programlisting><![ CDATA [<screen>&prompt.user; <userinput>ls -1</userinput> -foo1 -foo2 -foo3 -&prompt.user; <userinput>ls -1 | grep foo2</userinput> -foo2 -&prompt.user; <userinput>su</userinput> -<prompt>Password: </prompt> -&prompt.root; <userinput>cat foo2</userinput> -This is the file called 'foo2'</screen>]]></programlisting> - - <para>Appearance:</para> - - <screen>&prompt.user; <userinput>ls -1</userinput> -foo1 -foo2 -foo3 -&prompt.user; <userinput>ls -1 | grep foo2</userinput> -foo2 -&prompt.user; <userinput>su</userinput> -<prompt>Password: </prompt> -&prompt.root; <userinput>cat foo2</userinput> -This is the file called 'foo2'</screen> - </example> - - <note> - <para>Even though we are displaying the contents of the file - <filename>foo2</filename>, it is <emphasis>not</emphasis> marked - up as <sgmltag>programlisting</sgmltag>. Reserve - <sgmltag>programlisting</sgmltag> for showing fragments of files - outside the context of user actions.</para> - </note> - </sect3> - </sect2> - - <sect2> - <title>In-line elements</title> - - <sect3> - <title>Emphasising information</title> - - <para>When you want to emphasise a particular word or phrase, use - <sgmltag>emphasis</sgmltag>. This may be presented as italic, or - bold, or might be spoken differently with a text-to-speech - system.</para> - - <para>There is no way to change the presentation of the emphasis - within your document, no equivalent of HTML's <sgmltag>b</sgmltag> - and <sgmltag>i</sgmltag>. If the information you are presenting is - important then consider presenting it in - <sgmltag>important</sgmltag> rather than - <sgmltag>emphasis</sgmltag>.</para> - - <example> - <title><sgmltag>emphasis</sgmltag></title> - - <para>Use:</para> - - <programlisting><![ CDATA [<para>FreeBSD is without doubt <emphasis>the</emphasis> - premiere Unix like operating system for the Intel architecture.</para>]]></programlisting> - - <para>Appearance:</para> - - <para>FreeBSD is without doubt <emphasis>the</emphasis> premiere Unix - like operating system for the Intel architecture.</para> - </example> - </sect3> - - <sect3> - <title>Applications, commands, options, and cites</title> - - <para>You will frequently want to refer to both applications and - commands when writing for the Handbook. The distinction between - them is simple: an application is the name for a suite (or possibly - just 1) of programs that fulfil a particular task. A command is the - name of a program that the user can run.</para> - - <para>In addition, you will occasionally need to list one or more of - the options that a command might take.</para> - - <para>Finally, you will often want to list a command with its manual - section number, in the “command(number)” format so - common in Unix manuals.</para> - - <para>Mark up application names with - <sgmltag>application</sgmltag>.</para> - - <para>When you want to list a command with its manual section number - (which should be most of the time) the DocBook element is - <sgmltag>citerefentry</sgmltag>. This will contain a further two - elements, <sgmltag>refentrytitle</sgmltag> and - <sgmltag>manvolnum</sgmltag>. The content of - <sgmltag>refentrytitle</sgmltag> is the name of the command, and the - content of <sgmltag>manvolnum</sgmltag> is the manual page - section.</para> - - <para>This can be cumbersome to write, and so a series of <link - linkend="sgml-primer-general-entities">general entities</link> - have been created to make this easier. Each entity takes the form - <literal>&man.<replaceable>manual-page</replaceable>.<replaceable>manual-section</replaceable>;</literal>.</para> - - <para>The file that contains these entities is in - <filename>doc/share/sgml/man-refs.ent</filename>, and can be - referred to using this FPI:</para> - - <programlisting>PUBLIC "-//FreeBSD//ENTITIES DocBook Manual Page Entities//EN"</programlisting> - - <para>Therefore, the introduction to your documentation will probably - look like this:</para> - - <programlisting><!DOCTYPE book PUBLIC "-//FreeBSD//DTD DocBook V4.1-Based Extension//EN" [ - -<!ENTITY % man PUBLIC "-//FreeBSD//ENTITIES DocBook Manual Page Entities//EN"> -%man; - -… - -]></programlisting> - - <para>Use <sgmltag>command</sgmltag> when you want to include a - command name “in-line” but present it as something the - user should type in.</para> - - <para>Use <sgmltag>option</sgmltag> to mark up a command's - options.</para> - - <para>This can be confusing, and sometimes the choice is not always - clear. Hopefully this example makes it clearer.</para> - - <example> - <title>Applications, commands, and options.</title> - - <para>Use:</para> - - <programlisting><![ CDATA [<para><application>Sendmail</application> is the most - widely used Unix mail application.</para> - -<para><application>Sendmail</application> includes the - <citerefentry> - <refentrytitle>sendmail</refentrytitle> - <manvolnum>8</manvolnum> - </citerefentry>, &man.mailq.8;, and &man.newaliases.8; - programs.</para> - -<para>One of the command line parameters to <citerefentry> - <refentrytitle>sendmail</refentrytitle> - <manvolnum>8</manvolnum> - </citerefentry>, <option>-bp</option>, will display the current - status of messages in the mail queue. Check this on the command - line by running <command>sendmail -bp</command>.</para>]]></programlisting> - - <para>Appearance:</para> - - <para><application>Sendmail</application> is the most widely used - Unix mail application.</para> - - <para><application>Sendmail</application> includes the - <citerefentry> - <refentrytitle>sendmail</refentrytitle> - <manvolnum>8</manvolnum> - </citerefentry>, <citerefentry> - <refentrytitle>mailq</refentrytitle> - <manvolnum>8</manvolnum> - </citerefentry>, and <citerefentry> - <refentrytitle>newaliases</refentrytitle> - <manvolnum>8</manvolnum> - </citerefentry> programs.</para> - - <para>One of the command line parameters to <citerefentry> - <refentrytitle>sendmail</refentrytitle> - <manvolnum>8</manvolnum> - </citerefentry>, <option>-bp</option>, will display the current - status of messages in the mail queue. Check this on the command - line by running <command>sendmail -bp</command>.</para> - </example> - - <note> - <para>Notice how the - <literal>&man.<replaceable>command</replaceable>.<replaceable>section</replaceable>;</literal> notation is easier to follow.</para> - </note> - </sect3> - - <sect3> - <title>Files, directories, extensions</title> - - <para>Whenever you wish to refer to the name of a file, a directory, - or a file extension, use <sgmltag>filename</sgmltag>.</para> - - <example> - <title><sgmltag>filename</sgmltag></title> - - <para>Use:</para> - - <programlisting><![ CDATA [<para>The SGML source for the Handbook in English can be - found in <filename>/usr/doc/en/handbook/</filename>. The first - file is called <filename>handbook.sgml</filename> in that - directory. You should also see a <filename>Makefile</filename> - and a number of files with a <filename>.ent</filename> - extension.</para>]]></programlisting> - - <para>Appearance:</para> - - <para>The SGML source for the Handbook in English can be found in - <filename>/usr/doc/en/handbook/</filename>. The first file is - called <filename>handbook.sgml</filename> in that directory. You - should also see a <filename>Makefile</filename> and a number of - files with a <filename>.ent</filename> extension.</para> - </example> - </sect3> - - <sect3> - <title>Devices</title> - - <note> - <title>FreeBSD extension</title> - - <para>These elements are part of the FreeBSD extension to DocBook, - and do not exist in the original DocBook DTD.</para> - </note> - - <para>When referring to devices you have two choices. You can either - refer to the device as it appears in <filename>/dev</filename>, or - you can use the name of the device as it appears in the kernel. For - this latter course, use <sgmltag>devicename</sgmltag>.</para> - - <para>Sometimes you will not have a choice. Some devices, such as - networking cards, do not have entries in <filename>/dev</filename>, - or the entries are markedly different from those entries.</para> - - <example> - <title><sgmltag>devicename</sgmltag></title> - - <para>Use:</para> - - <programlisting><![ CDATA [<para><devicename>sio</devicename> is used for serial - communication in FreeBSD. <devicename>sio</devicename> manifests - through a number of entries in <filename>/dev</filename>, including - <filename>/dev/ttyd0</filename> and <filename>/dev/cuaa0</filename>.</para> - -<para>By contrast, the networking devices, such as - <devicename>ed0</devicename> do not appear in <filename>/dev</filename>. - -<para>In MS-DOS, the first floppy drive is referred to as - <devicename>a:</devicename>. In FreeBSD it is - <filename>/dev/fd0</filename>.</para>]]></programlisting> - - <para>Appearance:</para> - - <para><devicename>sio</devicename> is used for serial communication - in FreeBSD. <devicename>sio</devicename> manifests through a - number of entries in <filename>/dev</filename>, including - <filename>/dev/ttyd0</filename> and - <filename>/dev/cuaa0</filename>.</para> - - <para>By contrast, the networking devices, such as - <devicename>ed0</devicename> do not appear in - <filename>/dev</filename>.</para> - - <para>In MS-DOS, the first floppy drive is referred to as - <devicename>a:</devicename>. In FreeBSD it is - <filename>/dev/fd0</filename>.</para> - </example> - </sect3> - - <sect3> - <title>Hosts, domains, IP addresses, and so forth</title> - - <note> - <title>FreeBSD extension</title> - - <para>These elements are part of the FreeBSD extension to DocBook, - and do not exist in the original DocBook DTD.</para> - </note> - - <para>You can markup identification information for networked - computers (hosts) in several ways, depending on the nature of the - information. All of them use <sgmltag>hostid</sgmltag> as the - element, with the <literal>role</literal> attribute selecting the - type of the marked up information.</para> - - <variablelist> - <varlistentry> - <term>No role attribute, or - <literal>role="hostname"</literal></term> - - <listitem> - <para>With no role attribute (i.e., - <sgmltag>hostid</sgmltag>...<sgmltag>hostid</sgmltag> the - marked up information is the simple hostname, such as - <literal>freefall</literal> or <literal>wcarchive</literal>. - You can explicitly specify this with - <literal>role="hostname"</literal>.</para> - </listitem> - </varlistentry> - - <varlistentry> - <term><literal>role="domainname"</literal></term> - - <listitem> - <para>The text is a domain name, such as - <literal>FreeBSD.org</literal> or - <literal>ngo.org.uk</literal>. There is no hostname - component.</para> - </listitem> - </varlistentry> - - <varlistentry> - <term><literal>role="fqdn"</literal></term> - - <listitem> - <para>The text is a Fully Qualified Domain Name, with both - hostname and domain name parts.</para> - </listitem> - </varlistentry> - - <varlistentry> - <term><literal>role="ipaddr"</literal></term> - - <listitem> - <para>The text is an IP address, probably expressed as a dotted - quad.</para> - </listitem> - </varlistentry> - - <varlistentry> - <term><literal>role="ip6addr"</literal></term> - - <listitem> - <para>The text is an IPv6 address.</para> - </listitem> - </varlistentry> - - <varlistentry> - <term><literal>role="netmask"</literal></term> - - <listitem> - <para>The text is a network mask, which might be expressed as a - dotted quad, a hexadecimal string, or as a - <literal>/</literal> followed by a number.</para> - </listitem> - </varlistentry> - - <varlistentry> - <term><literal>role="mac"</literal></term> - - <listitem> - <para>The text is an ethernet MAC address, expressed as a series - of 2 digit hexadecimal numbers seperated by colons.</para> - </listitem> - </varlistentry> - </variablelist> - - <example> - <title><sgmltag>hostid</sgmltag> and roles</title> - - <para>Use:</para> - - <programlisting><![ CDATA [<para>The local machine can always be referred to by the - name <hostid>localhost</hostid>, which will have the IP address - <hostid role="ipaddr">127.0.0.1</hostid>.</para> - -<para>The <hostid role="domainname">FreeBSD.org</hostid> domain - contains a number of different hosts, including - <hostid role="fqdn">freefall.FreeBSD.org</hostid> and - <hostid role="fqdn">bento.FreeBSD.org</hostid>.</para> - -<para>When adding an IP alias to an interface (using - <command>ifconfig</command>) <emphasis>always</emphasis> use a - netmask of <hostid role="netmask">255.255.255.255</hostid> - (which can also be expressed as <hostid - role="netmask">0xffffffff</hostid>.</para> - -<para>The MAC address uniquely identifies every network card in - in existence. A typical MAC address looks like <hostid - role="mac">08:00:20:87:ef:d0</hostid>.</para>]]></programlisting> - - <para>Appearance:</para> - - <para>The local machine can always be referred to by the name - <hostid>localhost</hostid>, which will have the IP address <hostid - role="ipaddr">127.0.0.1</hostid>.</para> - - <para>The <hostid role="domainname">FreeBSD.org</hostid> domain - contains a number of different hosts, including <hostid - role="fqdn">freefall.FreeBSD.org</hostid> and <hostid - role="fqdn">bento.FreeBSD.org</hostid>.</para> - - <para>When adding an IP alias to an interface (using - <command>ifconfig</command>) <emphasis>always</emphasis> use a - netmask of <hostid role="netmask">255.255.255.255</hostid> (which - can also be expressed as <hostid - role="netmask">0xffffffff</hostid>.</para> - - <para>The MAC address uniquely identifies every network card in - existence. A typical MAC address looks like <hostid - role="mac">08:00:20:87:ef:d0</hostid>.</para> - </example> - </sect3> - - <sect3> - <title>Usernames</title> - - <note> - <title>FreeBSD extension</title> - - <para>These elements are part of the FreeBSD extension to DocBook, - and do not exist in the original DocBook DTD.</para> - </note> - - <para>When you need to refer to a specific username, such as - <literal>root</literal> or <literal>bin</literal>, use - <sgmltag>username</sgmltag>.</para> - - <example> - <title><sgmltag>username</sgmltag></title> - - <para>Use:</para> - - <programlisting><![ CDATA [<para>To carry out most system administration functions you - will need to be <username>root</username>.</para>]]></programlisting> - - <para>Appearance:</para> - - <para>To carry out most system administration functions you will - need to be <username>root</username>.</para> - </example> - </sect3> - - <sect3> - <title>Describing <filename>Makefile</filename>s</title> - - <note> - <title>FreeBSD extension</title> - - <para>These elements are part of the FreeBSD extension to DocBook, - and do not exist in the original DocBook DTD.</para> - </note> - - <para>Two elements exist to describe parts of - <filename>Makefile</filename>s, <sgmltag>maketarget</sgmltag> and - <sgmltag>makevar</sgmltag>.</para> - - <para><sgmltag>maketarget</sgmltag> identifies a build target exported - by a <filename>Makefile</filename> that can be given as a parameter - to <command>make</command>. <sgmltag>makevar</sgmltag> identifies a - variable that can be set (in the environment, on the - <command>make</command> command line, or within the - <filename>Makefile</filename>) to influence the process.</para> - - <example> - <title><sgmltag>maketarget</sgmltag> and - <sgmltag>makevar</sgmltag></title> - - <para>Use:</para> - - <programlisting><![ CDATA [<para>Two common targets in a <filename>Makefile</filename> - are <maketarget>all</maketarget> and <maketarget>clean</maketarget>.</para> - -<para>Typically, invoking <maketarget>all</maketarget> will rebuild the - application, and invoking <maketarget>clean</maketarget> will remove - the temporary files (<filename>.o</filename> for example) created by - the build process.</para> - -<para><maketarget>clean</maketarget> may be controlled by a number of - variables, including <makevar>CLOBBER</makevar> and - <makevar>RECURSE</makevar>.</para>]]></programlisting> - - <para>Appearance:</para> - - <para>Two common targets in a <filename>Makefile</filename> are - <maketarget>all</maketarget> and - <maketarget>clean</maketarget>.</para> - - <para>Typically, invoking <maketarget>all</maketarget> will rebuild - the application, and invoking <maketarget>clean</maketarget> will - remove the temporary files (<filename>.o</filename> for example) - created by the build process.</para> - - <para><maketarget>clean</maketarget> may be controlled by a number - of variables, including <makevar>CLOBBER</makevar> and - <makevar>RECURSE</makevar>.</para> - </example> - </sect3> - - <sect3> - <title>Literal text</title> - - <para>You will often need to include “literal” text in the - Handbook. This is text that is excerpted from another file, or - which should be copied from the Handbook into another file - verbatim.</para> - - <para>Some of the time, <sgmltag>programlisting</sgmltag> will be - sufficient to denote this text. <sgmltag>programlisting</sgmltag> - is not always appropriate, particularly when you want to include a - portion of a file “in-line” with the rest of the - paragraph.</para> - - <para>On these occasions, use <sgmltag>literal</sgmltag>.</para> - - <example> - <title><sgmltag>literal</sgmltag></title> - - <para>Use:</para> - - <programlisting><![ CDATA [<para>The <literal>maxusers 10</literal> line in the kernel - configuration file determines the size of many system tables, and is - a rough guide to how many simultaneous logins the system will - support.</para>]]></programlisting> - - <para>Appearance:</para> - - <para>The <literal>maxusers 10</literal> line in the kernel - configuration file determines the size of many system tables, and - is a rough guide to how many simultaneous logins the system will - support.</para> - </example> - </sect3> - - <sect3> - <title>Showing items that the user <emphasis>must</emphasis> fill - in</title> - - <para>There will often be times when you want to show the user what to - do, or refer to a file, or command line, or similar, where the user - can not simply copy the examples that you provide, but must instead - include some information themselves.</para> - - <para><sgmltag>replaceable</sgmltag> is designed for this eventuality. - Use it <emphasis>inside</emphasis> other elements to indicate parts - of that element's content that the user must replace.</para> - - <example> - <title><sgmltag>replaceable</sgmltag></title> - - <para>Use:</para> - - <programlisting><![ CDATA [<informalexample> - <screen>&prompt.user; <userinput>man <replaceable>command</replaceable></userinput></screen> -</informalexample>]]></programlisting> - - <para>Appearance:</para> - - <informalexample> - <screen>&prompt.user; <userinput>man <replaceable>command</replaceable></userinput></screen> - </informalexample> - - <para><sgmltag>replaceable</sgmltag> can be used in many different - elements, including <sgmltag>literal</sgmltag>. This example also - shows that <sgmltag>replaceable</sgmltag> should only be wrapped - around the content that the user <emphasis>is</emphasis> meant to - provide. The other content should be left alone.</para> - - <para>Use:</para> - - <programlisting><![ CDATA [<para>The <literal>maxusers <replaceable>n</replaceable></literal> - line in the kernel configuration file determines the size of many system - tables, and is a rough guide to how many simultaneous logins the system will - support.</para> - -<para>For a desktop workstation, <literal>32</literal> is a good value - for <replaceable>n</replaceable>.</para>]]></programlisting> - - <para>Appearance:</para> - - <para>The <literal>maxusers <replaceable>n</replaceable></literal> - line in the kernel configuration file determines the size of many - system tables, and is a rough guide to how many simultaneous - logins the system will support.</para> - - <para>For a desktop workstation, <literal>32</literal> is a good - value for <replaceable>n</replaceable>.</para> - </example> - </sect3> - </sect2> - - <sect2> - <title>Images</title> - - <important> - <para>Image support in the documentation is currently extremely - experimental. I think the mechanisms described here are unlikely to - change, but that's not guaranteed.</para> - - <para>You will also need to install the - <filename>graphics/ImageMagick</filename> port, which is used to - convert between the different image formats. This is a big port, - and most of it is not required. However, while we're working on the - <filename>Makefile</filename>s and other infrastructure it makes - things easier. This port is <emphasis>not</emphasis> in the - <filename>textproc/docproj</filename> meta port, you must install it - by hand.</para> - - <para>The best example of what follows in practice is the - <filename>en_US.ISO_8859-1/articles/vm-design/</filename> document. - If you're unsure of the description that follows, take a look at the - files in that directory to see how everything hangs togther. - Experiment with creating different formatted versions of the - document to see how the image markup appears in the formatted - output.</para> - </important> - - <sect3> - <title>Image formats</title> - - <para>We currently support two formats for images. The format you - should use will depend on the nature of your image.</para> - - <para>For images that are primarily vector based, such as network - diagrams, timelines, and similar, use Encapsulated Postscript, and - make sure that your images have the <filename>.eps</filename> - extension.</para> - - <para>For bitmaps, such as screen captures, use the Portable Network - Graphic format, and make sure that your images have the - <filename>.png</filename> extension.</para> - - <para>These are the <emphasis>only</emphasis> formats in which images - should be committed to the CVS repository.</para> - - <para>Use the right format for the right image. It is to be expected - that your documentation will have a mix of EPS and PNG images. The - <filename>Makefile</filename>s ensure that the correct format image - is chosen depending on the output format that you use for your - documentation. <emphasis>Do not commit the same image to the - repository in two different formats</emphasis>.</para> - - <important> - <para>It is anticipated that the Documentation Project will switch to - using the Scalable Vector Graphic (SVG) format for vector images. - However, the current state of SVG capable editing tools makes this - impractical.</para> - </important> - </sect3> - - <sect3> - <title>Markup</title> - - <para>The markup for an image is relatively simple. First, markup a - <sgmltag>mediaobject</sgmltag>. The <sgmltag>mediaobject</sgmltag> - can contain other, more specific objects. We are concerned with - two, the <sgmltag>imageobject</sgmltag> and the - <sgmltag>textobject</sgmltag>.</para> - - <para>You should include one <sgmltag>imageobject</sgmltag>, and two - <sgmltag>textobject</sgmltag> elements. The - <sgmltag>imageobject</sgmltag> will point to the name of the image - file that will be used (without the extension). The - <sgmltag>textobject</sgmltag> elements contain information that will - be presented to the user as well as, or instead of, the - image.</para> - - <para>There are two circumstances where this can happen.</para> - - <itemizedlist> - <listitem> - <para>When the reader is viewing the documentation in HTML. In - this case, each image will need to have associated alternate - text to show the user, typically whilst the image is loading, or - if they hover the mouse pointer over the image.</para> - </listitem> - - <listitem> - <para>When the reader is viewing the documentation in plain text. - In this case, each image should have an ASCII art equivalent to - show the user.</para> - </listitem> - </itemizedlist> - - <para>An example will probably make things easier to understand. - Suppose you have an image, called <filename>fig1</filename>, that - you want to include in the document. This image is of a rectangle - with an A inside it. The markup for this would be as - follows.</para> - - <programlisting><mediaobject> - <imageobject> - <imagedata fileref="fig1"> <co id="co-image-ext"> - </imageobject> - - <textobject> - <literallayout class="monospaced">+---------------+ <co id="co-image-literal"> -| A | -+---------------+</literallayout> - </textobject> - - <textobject> - <phrase>A picture</phrase> <co id="co-image-phrase"> - </textobject> -</mediaobject></programlisting> - - <calloutlist> - <callout arearefs="co-image-ext"> - <para>Include an <sgmltag>imagedata</sgmltag> element inside the - <sgmltag>imageobject</sgmltag> element. The - <literal>fileref</literal> attribute should contain the filename - of the image to include, without the extension. The stylesheets - will work out which extension should be added to the filename - automatically.</para> - </callout> - - <callout arearefs="co-image-literal"> - <para>The first <sgmltag>textobject</sgmltag> should contain a - <sgmltag>literallayout</sgmltag> element, where the - <literal>class</literal> attribute is set to - <literal>monospaced</literal>. This is your opportunity to - demonstrate your ASCII art skills. This content will be used if - the document is converted to plain text.</para> - - <para>Notice how the first and last lines of the content of the - <sgmltag>literallayout</sgmltag> element butt up next to the - element's tags. This ensures no extraneous white space is - included.</para> - </callout> - - <callout arearefs="co-image-phrase"> - <para>The second <sgmltag>textobject</sgmltag> should contain a - single <sgmltag>phrase</sgmltag> element. The contents of this - will become the <literal>alt</literal> attribute for the image - when this document is converted to HTML.</para> - </callout> - </calloutlist> - </sect3> - - <sect3> - <title><filename>Makefile</filename> entries</title> - - <para>Your images must be listed in the - <filename>Makefile</filename> in the <makevar>IMAGES</makevar> - variable. This variable should contain the name of all your - <emphasis>source</emphasis> images. For example, if you have - created three figures, <filename>fig1.eps</filename>, - <filename>fig2.png</filename>, <filename>fig3.png</filename>, then - your <filename>Makefile</filename> should have lines like this in - it.</para> - - <programlisting>… -IMAGES= fig1.eps fig2.png fig3.png -…</programlisting> - - <para>or</para> - - <programlisting>… -IMAGES= fig1.eps -IMAGES+= fig2.png -IMAGES+= fig3.png -…</programlisting> - - <para>Again, the <filename>Makefile</filename> will work out the - complete list of images it needs to build your source document, you - only need to list the image files <emphasis>you</emphasis> - provided.</para> - </sect3> - - <sect3> - <title>Images and chapters in subdirectories</title> - - <para>You must be careful when you separate your documentation in to - smaller files (see <xref linkend="sgml-primer-include-using-gen-entities">) in - different directories.</para> - - <para>Suppose you have a book with three chapters, and the chapters - are stored in their own directories, called - <filename>chapter1/chapter.sgml</filename>, - <filename>chapter2/chapter.sgml</filename>, and - <filename>chapter3/chapter.sgml</filename>. If each chapter has - images associated with it, I suggest you place those images in each - chapter's subdirectory (<filename>chapter1/</filename>, - <filename>chapter2/</filename>, and - <filename>chapter3/</filename>).</para> - - <para>However, if you do this you must include the directory names in - the <makevar>IMAGES</makevar> variable in the - <filename>Makefile</filename>, <emphasis>and</emphasis> you must - include the directory name in the <sgmltag>imagedata</sgmltag> - element in your document.</para> - - <para>For example, if you have <filename>chapter1/fig1.png</filename>, - then <filename>chapter1/chapter.sgml</filename> should - contain</para> - - <programlisting><mediaobject> - <imageobject> - <imagedata fileref="chapter1/fig1"> <co id="co-image-dir"> - </imageobject> - - … - -</mediaobject></programlisting> - - <calloutlist> - <callout arearefs="co-image-dir"> - <para>The directory name must be included in the - <literal>fileref</literal> attribute</para> - </callout> - </calloutlist> - - <para>The <filename>Makefile</filename> must contain</para> - - <programlisting>… -IMAGES= chapter1/fig1.png -…</programlisting> - - <para>Then everything should just work.</para> - </sect3> - </sect2> - - <sect2> - <title>Links</title> - - <note> - <para>Links are also in-line elements.</para> - </note> - - <sect3> - <title>Linking to other parts of the same document</title> - - <para>Linking within the same document requires you to to specify - where you are linking from (i.e., the text the user will click, or - otherwise indicate, as the source of the link) and where you are - linking to (the link's destination).</para> - - <para>Each element within DocBook has an attribute called - <literal>id</literal>. You can place text in this attribute to - uniquely name the element it is attached to.</para> - - <para>This value will be used when you specify the link - source.</para> - - <para>Normally, you will only be linking to chapters or sections, so - you would add the <literal>id</literal> attribute to these - elements.</para> - - <example> - <title><literal>id on chapters and sections</literal></title> - - <programlisting><![ CDATA [<chapter id="chapter1"> - <title>Introduction</title> - - <para>This is the introduction. It contains a subsection, - which is identified as well.</para> - - <sect1 id="chapter1-sect1"> - <title>Sub-sect 1</title> - - <para>This is the subsection.</para> - </sect1> -</chapter>]]></programlisting> - </example> - - <para>Obviously, you should use more descriptive values. The values - must be unique within the document (i.e., not just the file, but the - document the file might be included in as well). Notice how the - <literal>id</literal> for the subsection is constructed by appending - text to the <literal>id</literal> of the chapter. This helps to - ensure that they are unique.</para> - - <para>If you want to allow the user to jump into a specific portion of - the document (possibly in the middle of a paragraph or an example), - use <sgmltag>anchor</sgmltag>. This element has no content, but - takes an <literal>id</literal> attribute.</para> - - <example> - <title><sgmltag>anchor</sgmltag></title> - - <programlisting><![ CDATA [<para>This paragraph has an embedded - <anchor id="para1">link target in it. It won't show up in - the document.</para>]]></programlisting> - </example> - - <para>When you want to provide the user with a link they can activate - (probably by clicking) to go to a section of the document that has - an <literal>id</literal> attribute, you can use either - <sgmltag>xref</sgmltag> or <sgmltag>link</sgmltag>.</para> - - <para>Both of these elements have a <literal>linkend</literal> - attribute. The value of this attribute should be the value that you - have used in a <literal>id</literal> attribute (it does not matter - if that value has not yet occurred in your document; this will work - for forward links as well as backward links).</para> - - <para>If you use <sgmltag>xref</sgmltag> then you have no control over - the text of the link. It will be generated for you.</para> - - <example> - <title>Using <sgmltag>xref</sgmltag></title> - - <para>Assume that this fragment appears somewhere in a document that - includes the <literal>id</literal> example;</para> - - <programlisting><![ CDATA [<para>More information can be found - in <xref linkend="chapter1">.</para> - -<para>More specific information can be found - in <xref linkend="chapter1-sect1">.</para>]]></programlisting> - - <para>The text of the link will be generated automatically, and will - look like (<emphasis>emphasised</emphasis> text indicates the text - that will be the link);</para> - - <blockquote> - <para>More information can be found in <emphasis>Chapter - One</emphasis>.</para> - - <para>More specific information can be found in <emphasis>the - section called Sub-sect 1</emphasis>.</para> - </blockquote> - </example> - - <para>Notice how the text from the link is derived from the section - title or the chapter number.</para> - - <note> - <para>This means that you <emphasis>can not</emphasis> use - <sgmltag>xref</sgmltag> to link to an <literal>id</literal> - attribute on an <sgmltag>anchor</sgmltag> element. The - <sgmltag>anchor</sgmltag> has no content, so the - <sgmltag>xref</sgmltag> can not generate the text for the - link.</para> - </note> - - <para>If you want to control the text of the link then use - <sgmltag>link</sgmltag>. This element wraps content, and the - content will be used for the link.</para> - - <example> - <title>Using <sgmltag>link</sgmltag></title> - - <para>Assume that this fragment appears somewhere in a document that - includes the <literal>id</literal> example.</para> - - <programlisting><![ CDATA [<para>More information can be found in - <link linkend="chapter1">the first chapter</link>.</para> - -<para>More specific information can be found in - <link linkend="chapter1-sect1>this</link> section.</para>]]></programlisting> - - <para>This will generate the following - (<emphasis>emphasised</emphasis> text indicates the text that will - be the link);</para> - - <blockquote> - <para>More information can be found in <emphasis>the first - chapter</emphasis>.</para> - - <para>More specific information can be found in - <emphasis>this</emphasis> section.</para> - </blockquote> - </example> - - <note> - <para>That last one is a bad example. Never use words like - “this” or “here” as the source for the - link. The reader will need to hunt around the surrounding context - to see where the link is actually taking them.</para> - </note> - - <note> - <para>You <emphasis>can</emphasis> use <sgmltag>link</sgmltag> to - include a link to an <literal>id</literal> on an - <sgmltag>anchor</sgmltag> element, since the - <sgmltag>link</sgmltag> content defines the text that will be used - for the link.</para> - </note> - </sect3> - - <sect3> - <title>Linking to documents on the WWW</title> - - <para>Linking to external documents is much simpler, as long as you - know the URL of the document you want to link to. Use - <sgmltag>ulink</sgmltag>. The <literal>url</literal> attribute is - the URL of the page that the link points to, and the content of the - element is the text that will be displayed for the user to - activate.</para> - - <example> - <title><sgmltag>ulink</sgmltag></title> - - <para>Use:</para> - - <programlisting><![ CDATA [<para>Of course, you could stop reading this document and - go to the <ulink url="http://www.FreeBSD.org/">FreeBSD - home page</ulink> instead.</para>]]></programlisting> - - <para>Appearance:</para> - - <para>Of course, you could stop reading this document and go to the - <ulink url="http://www.FreeBSD.org/">FreeBSD home page</ulink> - instead.</para> - </example> - </sect3> - </sect2> - </sect1> - - <sect1> - <title>* LinuxDoc</title> - - <para>LinuxDoc is an adaptation of the QWERTZ DTD, first adopted by the - <ulink url="http://www.linuxdoc.org/">Linux Documentation - Project</ulink>, and subsequently adopted by the FreeBSD Documentation - Project.</para> - - <para>The LinuxDoc DTD contains primarily appearance related markup rather - than content related markup (i.e., it describes what something looks - like rather than what it is).</para> - - <para>Both the FreeBSD Documentation Project and the Linux Documentation - Project are migrating from the LinuxDoc DTD to the DocBook DTD.</para> - - <para>The LinuxDoc DTD is available from the ports collection in the - <filename>textproc/linuxdoc</filename> category.</para> - </sect1> -</chapter> - - -<!-- - Local Variables: - mode: sgml - sgml-declaration: "../chapter.decl" - sgml-indent-data: t - sgml-omittag: nil - sgml-always-quote-attributes: t - sgml-parent-document: ("../book.sgml" "part" "chapter") - End: ---> - |