ch49.htm

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

can be handled by a normal user. If you intend to use port 210, you don't have to

specify the number in the command line, although the <TT>-p</TT> option still must

be used.</P>

<P>If you want to let <TT>inetd</TT> handle the <TT>waisserver</TT> startup, you

need to ensure that the file <TT>/etc/services</TT> has an entry for WAIS. The line

in the <TT>/etc/services</TT> file looks like</P>

<PRE><FONT COLOR="#0066FF">z3950   210/tcp   #WAIS

</FONT></PRE>

<P>where <TT>210</TT> is the port number WAIS uses, and <TT>tcp</TT> is the protocol.

After modifying or verifying the entry in <TT>/etc/services</TT>, you need to add

a WAIS entry to the <TT>inetd.conf</TT> file to start up <TT>waisserver</TT> whenever

a request is received on port 210 (or whatever other port you are using). The entry

looks like</P>

<PRE><FONT COLOR="#0066FF">z3950   stream   tcp   nowait   root/usr/local/bin/waisserver/waisserver.d 

-u  username -d /usr/wais/wais_index

</FONT></PRE>

<P>where the options are the same as for the command line startup mentioned previously.

The daemon <TT>waisserver.d</TT> is used when starting up in <TT>inetd</TT> mode,

instead of <TT>waisserver</TT>. Again you can use the <TT>-e</TT> option to log activity

to a file.

<CENTER>

<H3><A NAME="Heading10<FONT COLOR="#000077">Building Your WAIS Indexes</FONT></H3>

</CENTER>

<P>Once you have the freeWAIS server ready to run and everything seems to be working,

it's time to provide some content for your WAIS system. Usually, documents are the

primary source of information for WAIS, although you can index any type of file.

The key step to providing WAIS service is to build the WAIS index using the <TT>waisindex</TT>

command. The <TT>waisindex</TT> command can be a bit obtuse at times, but a little

practice and some trial-and-error fiddling will help you master its somewhat awkward

behavior.</P>

<P>The <TT>waisindex</TT> program works by examining all the data in the files in

which you want to create an index. From its examination, <TT>waisindex</TT> usually

generates seven different index files (depending on the content and your commands).

Each file holds a list of unique words in the documents. The different index files

are then combined into one large database, often called the &quot;source&quot; (or

&quot;WAIS source&quot;). Whenever a client WAIS package submits a search, the search

strings are compared to the source, and the results displayed with accuracy analysis

(the match score).



<DL>

	<DT></DT>

</DL>





<DL>

	<DD>

<HR>

<A NAME="Heading11<FONT COLOR="#000077"><B>NOTE: </B></FONT><FONT COLOR="#000000">T</FONT>he

	use of <TT>waisindex</TT> enables a client search to proceed much more quickly because

	the keywords in the data files have already been extracted. However, the mass of

	data in the index files can be sizable, so allow plenty of disk space for a WAIS

	server to work with. (For a typical WAIS site, assume at least double the amount

	of room needed for the source files.) 

<HR>



</DL>



<CENTER>

<H4><A NAME="Heading12<FONT COLOR="#000077">WAIS Index Files</FONT></H4>

</CENTER>

<P>The freeWAIS index files are not usually readable by a system user (although one

or two files can be read with some success). Usually, <TT>waisindex</TT> creates

seven index files, although the number may vary depending on requirements. Each index

file has a specific file extension to show its purpose, based on a root name (specified

on the <TT>waisindex</TT> command line, or defaulting to <TT>index</TT>). The index

files and their purposes are listed here: <TT>index.doc</TT> A document file that

contains a table with the filename, a headline (title) from the file, the location

of the first and last characters of an entry, the length of the document, the number

of lines in the document, and the time and date the document was created.</P>

<P><TT>index.dct</TT> A dictionary file that contains a list of every unique word

in the files cross-indexed to the inverted file.</P>

<P><TT>index.fn</TT> A filename file that contains a table with a list of the filenames,

the date they were created in the index, and the type of file.</P>

<P><TT>index.hl</TT> A headline file that contains a table of all headlines (titles).

The headline is displayed in the search output when a match occurs.</P>

<P><TT>index.inv</TT> Inverted files that contain a table associating every unique

word in all the files with a pointer to the files themselves and the word's importance

(determined by how close the word is to the start of the file, the number of times

the word occurs in the document, and the percentage of times the word appears in

the document).</P>

<P><TT>index.src</TT> A source description file that contains descriptions of the

information indexed, including the host name and IP address, the port watched by

WAIS, the source filename, any cost information for the service, the headline of

the service, a description of the source, and the e-mail address of the administrator.

The source description file is editable by ASCII editors. We will look at this file

in a little more detail shortly.





<BLOCKQUOTE>

	<P><TT>index.status</TT> A status file containing user-defined information.



</BLOCKQUOTE>



<P>The source description file is a standard ASCII file that is read by <TT>waisindex</TT>

at intervals to see if information has changed. If the changes are significant, <TT>waisindex</TT>

updates its internal information. A sample source file looks like this:</P>

<PRE><FONT COLOR="#0066FF"> (:source

   :version 2

   :ip-address &quot;147.120.0.10&quot;

   :ip-name: &quot;wizard.tpci.com&quot;

   :tcp-port 210

   :database-name &quot;Linux stuff&quot;

   :cost 0.00

   :cost-unit: free

   :maintainer &quot;[e-mail]&quot;

   :subjects &quot;Everything you need to know about Linux&quot;

   :description &quot;If you need to know something about Linux, it's here.&quot;

</FONT></PRE>

<P>You should edit this file when you set up freeWAIS because the default descriptions

are rather sparse and useless.

<CENTER>

<H4><A NAME="Heading13<FONT COLOR="#000077">The waisindex Command</FONT></H4>

</CENTER>

<P>The <TT>waisindex</TT> command allows a number of options, some of which you have

seen earlier in this chapter. The following list contains the primary <TT>waisindex</TT>

options of interest to most users:<BR>



<TABLE BORDER="0" WIDTH="100%">

	<TR>

		<TD WIDTH="9%" VALIGN="TOP">

			<UL>

				<LI>&#160;

			</UL>

		</TD>

		<TD WIDTH="15%" VALIGN="TOP"><TT>-a</TT></TD>

		<TD WIDTH="76%" VALIGN="TOP">Appends data to an existing index file (used to update index files instead of regenerating

			them each time a new document is added).</TD>

	</TR>

	<TR>

		<TD WIDTH="9%" VALIGN="TOP">

			<UL>

				<LI>&#160;

			</UL>

		</TD>

		<TD WIDTH="15%" VALIGN="TOP"><TT>-contents</TT></TD>

		<TD WIDTH="76%" VALIGN="TOP"><TT> </TT>Indexes the file contents (default action).</TD>

	</TR>

	<TR>

		<TD WIDTH="9%" HEIGHT="27" VALIGN="TOP">

			<UL>

				<LI>&#160;

			</UL>

		</TD>

		<TD WIDTH="15%" HEIGHT="27" VALIGN="TOP"><TT>-d</TT></TD>

		<TD WIDTH="76%" HEIGHT="27" VALIGN="TOP">Gives the filename root for index files (for example, <TT>-d /usr/wais/foo</TT> named

			all index files as <TT>/usr/wais/foo.</TT>xxx).</TD>

	</TR>

	<TR>

		<TD WIDTH="9%" VALIGN="TOP">

			<UL>

				<LI>&#160;

			</UL>

		</TD>

		<TD WIDTH="15%" VALIGN="TOP"><TT>-e</TT></TD>

		<TD WIDTH="76%" VALIGN="TOP">Gives the name of the log file for error information (default is <TT>stderr</TT>--usually

			the console--although you can specify <TT>-s</TT> for <TT>/dev/null</TT>).</TD>

	</TR>

	<TR>

		<TD WIDTH="9%" VALIGN="TOP">

			<UL>

				<LI>&#160;

			</UL>

		</TD>

		<TD WIDTH="15%" VALIGN="TOP"><TT>-export</TT></TD>

		<TD WIDTH="76%" VALIGN="TOP">Adds the host name and TCP port to descriptions for easier Internet access.</TD>

	</TR>

	<TR>

		<TD WIDTH="9%" VALIGN="TOP">

			<UL>

				<LI>&#160;

			</UL>

		</TD>

		<TD WIDTH="15%" VALIGN="TOP"><TT>-l</TT></TD>

		<TD WIDTH="76%" VALIGN="TOP">Gives the level of log messages. Valid values are <TT>0</TT>--no log, <TT>1</TT>--log

			only high priority errors and warnings, <TT>5</TT>--log medium priority errors and

			warnings, as well as index filename information, and <TT>10</TT>--log every event.</TD>

	</TR>

	<TR>

		<TD WIDTH="9%" VALIGN="TOP">

			<UL>

				<LI>&#160;

			</UL>

		</TD>

		<TD WIDTH="15%" VALIGN="TOP"><TT>-M</TT></TD>

		<TD WIDTH="76%" VALIGN="TOP">Links multiple types of files.</TD>

	</TR>

	<TR>

		<TD WIDTH="9%" VALIGN="TOP">

			<UL>

				<LI>&#160;

			</UL>

		</TD>

		<TD WIDTH="15%" VALIGN="TOP"><TT>-mem</TT></TD>

		<TD WIDTH="76%" VALIGN="TOP">Limits memory usage during indexing (the higher the number specified, the faster

			the indexing process and the more memory used).</TD>

	</TR>

	<TR>

		<TD WIDTH="9%" VALIGN="TOP">

			<UL>

				<LI>&#160;

			</UL>

		</TD>

		<TD WIDTH="15%" VALIGN="TOP"><TT>-nocontents</TT></TD>

		<TD WIDTH="76%" VALIGN="TOP">Prevents a file from being indexed (indexes only the document header and filename).</TD>

	</TR>

	<TR>

		<TD WIDTH="9%" VALIGN="TOP">

			<UL>

				<LI>&#160;

			</UL>

		</TD>

		<TD WIDTH="15%" VALIGN="TOP"><TT>-nopairs</TT></TD>

		<TD WIDTH="76%" VALIGN="TOP">Instructs <TT>waisindex</TT> to ignore adjacent capitalized words from being indexed

			together.</TD>

	</TR>

	<TR>

		<TD WIDTH="9%" VALIGN="TOP">

			<UL>

				<LI>&#160;

			</UL>

		</TD>

		<TD WIDTH="15%" VALIGN="TOP"><TT>-nopos</TT></TD>

		<TD WIDTH="76%" VALIGN="TOP">Ignores the location of keywords in a document when determining scores.</TD>

	</TR>

	<TR>

		<TD WIDTH="9%" VALIGN="TOP">

			<UL>

				<LI>&#160;

			</UL>

		</TD>

		<TD WIDTH="15%" VALIGN="TOP"><TT>-pairs</TT></TD>

		<TD WIDTH="76%" VALIGN="TOP">Indexes adjacent capitalized words as a single entry.</TD>

	</TR>

	<TR>

		<TD WIDTH="9%" VALIGN="TOP">

			<UL>

				<LI>&#160;

			</UL>

		</TD>

		<TD WIDTH="15%" VALIGN="TOP"><TT>-pos</TT></TD>

		<TD WIDTH="76%" VALIGN="TOP">Determines scores based on locations of keywords (proximity of keywords increases

			scores).</TD>

	</TR>

	<TR>

		<TD WIDTH="9%" VALIGN="TOP">

			<UL>

				<LI>&#160;

			</UL>

		</TD>

		<TD WIDTH="15%" VALIGN="TOP"><TT>-r</TT></TD>

		<TD WIDTH="76%" VALIGN="TOP">Recursive subdirectory indexing.</TD>

	</TR>

	<TR>

		<TD WIDTH="9%" VALIGN="TOP">

			<UL>

				<LI>&#160;

			</UL>

		</TD>

		<TD WIDTH="15%" VALIGN="TOP"><TT>-register</TT></TD>

		<TD WIDTH="76%" VALIGN="TOP">Registers your indexes with the WAIS Directory of Services.</TD>

	</TR>

	<TR>

		<TD WIDTH="9%" VALIGN="TOP">

			<UL>

				<LI>&#160;

			</UL>

		</TD>

		<TD WIDTH="15%" VALIGN="TOP"><TT>-stdin</TT></TD>

		<TD WIDTH="76%" VALIGN="TOP">Uses a filename from the keyboard instead of a filename on the command line.</TD>

	</TR>

	<TR>

		<TD WIDTH="9%" VALIGN="TOP">

			<UL>