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linux-unix130.linux.and.unix.ebooks130 linux and unix ebookslinuxLearning Linux - Collection of 12 E

	and use a filter or syntax checker afterward.



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<A NAME="Heading11<FONT COLOR="#000077"><B>NOTE:</B> </FONT>One of the best

	sites to look for new editors and filters is <TT>http://www.ncsaa.uiuc.edu/SDG/Software/Mosaic/Docs/FAQ-Software.html</TT>,

	which contains an up-to-date list of offerings.

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	<P>You can use any ASCII editor to write HTML pages, including simple screen-oriented

	editors based on <TT>vi</TT> or <TT>emacs</TT>. They all enable you to enter tags

	into a page of text, but the tags are treated as words with no special meaning. There

	is no validity checking performed by simple editors, because they simply don't understand

	HTML. There are some extensions for <TT>emacs</TT> and similar full-screen editors

	that provide a simple template check, but they are not rigorous in enforcing HTML

	styles.</P>



	<P>If you wish to use a plain editor, you should carefully check your document for

	the valid use of tags. One of the easiest methods of checking a document is to import

	it into an HTML editor that has strong HTML tag checking. Another easy method is

	to simply call up the document on your Web browser and carefully study its appearance.</P>

	<P>You can obtain a dedicated HTML authoring package from some sites, although they

	are not as common for Linux as for DOS and Windows. If you are running both operating

	systems, you can always develop your HTML documents in Windows, and then import them

	to Linux. There are several popular HTML tools for Windows, such as HTML Assistant,

	HTMLed, and HoTMetaL. A few of the WYSIWYG editors are also available for X, and

	hence run under Linux, such as HoTMetaL. Some HTML authoring tools are fully WYSIWYG,

	while others are character-based. Most offer strong verification systems for generated

	HTML code.</P>

	<P>An alternative to using a dedicated editor for HTML documents is to enhance an

	existing WYSIWYG word processor to handle HTML properly. The most commonly targeted

	word processor for these extensions is Word for Windows, Word Perfect, and Word for

	DOS. Several extension products are available in varying degrees of complexity. Most

	run under Windows; although a few have been ported to Linux.</P>

	<P>The advantage to using one of these extensions is that you retain a familiar editor

	and make use of the near-WYSIWYG features it can provide for HTML documents. Although

	it can't show you the final document in Web format, it can be close enough to prevent

	all but the most minor problems.</P>

	<P>CU_HTML is a template for Microsoft's Word for Windows that gives a very-near-to

	WYSIWYG view of HTML documents. Graphically, CU_HTML looks much the same as Word,

	but with a new toolbar and pull-down menu item. CU_HTML provides a number of different

	styles and a toolbar of oft-used tasks. Tasks such as linking documents are easy,

	as are most tasks that tend to worry new HTML document writers. Dialog boxes are

	used for many tasks, simplifying the interface considerably.</P>

	<P>The only major disadvantage to CU_HTML is that it can't be used to edit existing

	HTML documents if they are not in Word format. When CU_HTML creates an HTML document,

	there are two versions produced, one in HTML and the other as a Word DOC file. Without

	both, the document can't be edited. An existing document can be imported, but it

	loses all the tags.</P>

	<P>Like CU_HTML, ANT_HTML is an extension to Word. There are some advantages and

	disadvantages of ANT_HTML over CU_HTML. The documentation and help is better with

	ANT_HTML, and the toolbar is much better. It also has automatic insertion of opening

	and closing tags as needed.</P>

	<P>One system that has gained popularity among Linux users is tkWWW. This system

	is a tool for the Tcl language and its Tk extension for X. tkWWW is a combination

	of a Web browser and a near-WYSIWYG HTML editor. Although originally UNIX-based,

	tkWWW has been ported to several other platforms, including Windows and Macintosh.



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<A NAME="Heading12<FONT COLOR="#000077"><B>NOTE:</B> </FONT>tkWWW can be obtained

	through anonymous FTP to <TT>harbor.ecn.purdue.edu</TT> in the dir-ectory <TT>/pub/tcl/extensions</TT>.

	Copies of Tcl and Tk can be found in several sites depending on the platform required,

	although most distributions of Linux have Tcl and Tk included in the distribution

	set. As a starting point, try anonymous FTP to <TT>ftp.aud.alcatel.com</TT> in the

	directory <TT>tcl/extensions</TT>.

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	<P>When you create a Web page with tkWWW in editor mode, you can then flip modes

	to browser to see the same page properly formatted. In editor mode, most of the formatting

	is correct, but the tags are left visible. This makes for fast development of a Web

	page.</P>



	<P>Unfortunately, tkWWW must rely on Tk for its windowing, which tends to slow things

	down a bit on average processors. Also, the browser aspect of tkWWW is not impressive,

	using standard Tk frames. However, as a prototyping tool, tkWWW is very attractive,

	especially if you know the Tcl language.</P>

	<P>Another option is to use an HTML filter. HTML filters are tools that let you take

	a document produced with any kind of editor (including ASCII text editors) and convert

	the document to HTML. Filters are useful when you work in an editor that has its

	own proprietary format, such as Word.</P>

	<P>HTML filters are attractive if you want to continue working in your favorite editor

	and simply want a utility to convert your document with tags to HTML. Filters tend

	to be fast and easy to work with, because they take a filename as input and generate

	an HTML output file. The degree of error checking and reporting varies with the tool.</P>

	<P>There are filters available for most types of documents, many of which are available

	directly for Linux, or as source code that can be recompiled without modification

	under Linux. Word for Windows and Word for DOS documents can be converted to HTML

	with the CU_HTML and ANT_HTML extensions mentioned earlier. A few standalone conversion

	utilities have also begun to appear. The utility <TT>WPTOHTML</TT> converts WordPerfect

	documents to HTML. <TT>WPTOHTML</TT> is a set of macros for WordPerfect versions

	5.1 and 6.0. The WordPerfect filter can also be used with other word processor formats

	that WordPerfect can import.</P>

	<P>FrameMaker and FrameBuilder documents can be converted to HTML format with the

	tool FM2HTML. FM2HTML is a set of scripts that converts Frame documents to HTML,

	while preserving hypertext links and tables. It also handles GIF files without a

	problem. Because Frame documents are platform independent, Frame documents developed

	on a PC or Macintosh could be moved to the Linux platform and FM2HTML executed there.



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<A NAME="Heading13<FONT COLOR="#000077"><B>NOTE: </B></FONT>A copy of FM2HTML

	is available by anonymous FTP from <TT>bang.nta.no</TT> in the directory <TT>/pub</TT>.

	The UNIX set is called <TT>fm2html.tar.v.0.n.m.Z</TT>.

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	<P><TT>LaTeX</TT> and <TT>TeX</TT> files can be converted to HTML with several different

	utilities. There are quite a few Linux-based utilities available, including <TT>LATEXTOHTML</TT>,

	which can even handle inline <TT>LaTeX</TT> equations and links. For simpler documents,

	the utility <TT>VULCANIZE</TT> is faster but can't handle mathematical equations.

	Both<TT> LATEXTOHTML</TT> and <TT>VULCANIZE</TT> are Perl scripts.



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<A NAME="Heading14<FONT COLOR="#000077"><B>NOTE: </B></FONT><TT>LATEXTOHTML</TT>

	is available through anonymous FTP from <TT>ftp.tex.ac.uk</TT> in the directory <TT>pub/archive/support</TT>

	as the file <TT>latextohtml</TT>. <TT>VULCANIZE</TT> can be obtained from the Web

	site <TT>http://www.cis.upenn.edu/~mjd/vulcanize.html</TT>.

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	<P><TT>RTFTOHTML</TT> is a common utility for converting RTF format documents to

	HTML. Many word processors handle RTF formats, so an RTF document can be saved from

	your favorite word processor and then <TT>RTFTOHTML</TT> run to convert the files.



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<A NAME="Heading15<FONT COLOR="#000077"><B>NOTE: </B></FONT><TT>RTFTOHTML</TT>

	is available through <TT>http:\\www.w3.org/hypertext/www/tools/rtftohtml-2.6.html</TT>.

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	<H4><A NAME="Heading16<FONT COLOR="#000077">Maintaining HTML</FONT></H4>

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	<P>Once you have written a Web document and it is available to the world, your job

	doesn't end. Unless your document is a simple text file, you will have links to other

	documents or Web servers embedded. These links must be verified at regular intervals.

	Also, the integrity of your Web pages should be checked at intervals, to ensure that

	the flow of the document from your home page is correct.</P>

	<P>There are several utilities available to help you check links and also to scan

	the Web for other sites or documents you may want to provide a hyperlink to. These

	utilities tend to go by a number of names, such as robot, spider, or wanderer. They

	are all programs that move across the Web automatically, creating a list of Web links

	that you can access. (Spiders are similar to the Archie and Veronica tools for the

	Internet, although neither of these cover the Web.)</P>

	<P>Although they are often thought of as utilities for users only (to get a list

	of sites to try), spiders and their kin are useful for document authors, too, because

	they show potentially useful and interesting links. One of the best known spiders

	is the World Wide Web Worm, or WWWW. WWWW enables you to search for keywords or create

	a Boolean search, and can cover titles, documents, and several other search types

	(including a search of all known HTML pages).</P>

	<P>A similarly useful spider is WebCrawler, which is similar to WWWW except it can

	scan entire documents for matches of any keywords. It displays the result in an ordered

	list from closest match to least likely match.



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<A NAME="Heading17<FONT COLOR="#000077"><B>NOTE: </B></FONT>A copy of World

	Wide Web Worm can be obtained from <TT>http://www.cs.colorado.edu/home/mcbryan/WWWW.html</TT>.

	WebCrawler is available from <TT>http://www.biotech.washington.edu/WebCrawler/WebCrawler.html</TT>.

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	<P>A common problem with HTML documents as they age is that links that point to files

	or servers may no longer exist (because either the locations or the documents have

	changed). It is therefore good practice to validate the hyperlinks in a document

	on a regular basis. A popular hyperlink analyzer is HTML_ANALYZER. It examines each

	hyperlink and the contents of the hyperlink to ensure that they are consistent. HTML_ANALYZER

	functions by examining a document for all links, and then creating a text file that

	has a list of the links in it. HTML_ANALYZER uses the text files to compare the actual

	link content to what it should be.</P>



	<P>HTML_ANALYZER actually does three tests: It validates the availability of the

	documents pointed to by hyperlinks (called validation); it looks for hyperlink contents

	that occur in the database but are not themselves hyperlinks (called completeness);

	and it looks for a one-to-one relation between hyperlinks and the contents of the

	hyperlink (called consistency). Any deviations are listed for the user.</P>

	<P>HTML_ANALYZER users should have a good familiarity with HTML, their operating

	system, and the use of command-line driven analyzers. The tool must be compiled using

	the <TT>make</TT> utility prior to execution. There are several directories that

	must be created prior to running HTML_ANALYZER, and when it runs, it creates several

	temporary files when that are not cleaned up, so this is not a good utility for a

	novice.

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	<H3><A NAME="Heading18<FONT COLOR="#000077">Summary</FONT></H3>

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	<P>Setting up your home page requires you to either use an HTML authoring tool or

	write HTML code directly into an editor. The HTML language is beyond the scope of

	this book, but you should find several good guides to HTML at your bookstore. HTML

	is rather easy to learn. With the information in this chapter, you should be able

	to set up your Web site to enable anyone on the Internet to connect to you. Enjoy

	the Web!

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