usermanual.sgml
936 lines (757 with data), 39.4 kB
<!DOCTYPE BOOK PUBLIC "-//FreeBSD//DTD DocBook V4.1-Based Extension//EN" [
<!ENTITY RCL "<application>Recoll</application>">
<!ENTITY XAP "<application>Xapian</application>">
]>
<book lang="en">
<bookinfo>
<title>Recoll user manual</title>
<author>
<firstname>Jean-Francois</firstname>
<surname>Dockes</surname>
<affiliation>
<address><email>jean-francois.dockes@wanadoo.fr</email></address>
</affiliation>
</author>
<copyright>
<year>2005</year>
<holder role="mailto:jean-francois.dockes@wanadoo.fr">Jean-Francois
Dockes</holder>
</copyright>
<releaseinfo>$Id: usermanual.sgml,v 1.6 2006-03-04 10:09:59 dockes Exp $</releaseinfo>
<abstract>
<para>This document introduces full text search notions
and describes the installation and use of the &RCL; application.</para>
</abstract>
</bookinfo>
<chapter id="rcl.introduction">
<title>Introduction</title>
<sect1 id="rcl.introduction.tryit">
<title>Giving it a try</title>
<para>If you do not like reading manuals (who does?) and would
like to give &RCL; a try, just perform <link
linkend="rcl.install">installation</link> and start the
<command>recoll</command> user interface, which will index your
home directory and let you search it right after.</para>
<para>Do not do this if your home has a huge
number of documents and you do not want to wait or are very
short on disk space. In this case, you may want to edit the <link
linkend="rcl.indexing.config">configuration file</link> first to
restrict the indexed area.</para>
<para>Also be aware that you will need to install the
appropriate supporting applications for document types that need
them (for example <application>antiword</application> for
ms-word files), and that the default character set used to read
raw text files for indexing is iso8859-1, which may not be
appropriate for you.</para>
<sect1 id="rcl.introduction.search">
<title>Full text search</title>
<para>&RCL; is a full text search application. Full text search
applications let you find your data by content rather
than by external attributes (like a file name). More
specifically, they will let you specify words (terms) that
should or should not appear in the text you are looking for,
and return a list of matching documents, ordered so that the
most <emphasis>relevant</emphasis> documents will appear
first.</para>
<para>You do not need to remember in what file or email message you
stored a given piece of information. You just ask for related
terms, and the tool will return a list of documents where
those terms are prominent.</para>
<para>This mode of operation has been made very familiar by www
search engines.</para>
<para>The notion of relevance is a difficult one, as only you, the
user, actually know which documents are relevant to your search,
and the application can only try a guess. The quality of this
guess is probably the most important element for a search
application.</para>
<para>In many cases, you are looking for all the forms of a
word, not for a specific form or spelling. These different
forms may include plurals, different tenses for a verb, or
terms derived from the same root or <emphasis>stem</emphasis>
(exemple: floor, floors, floored, floorings...). &RCL; will by
default expand queries to all such related terms (words that
reduce to the same stem). This expansion can be disabled at
search time.</para>
<para>Stemming, by itself, does not provide for misspellings or
phonetic searches. &RCL; currently does not support these.</para>
</sect1>
<sect1 id="rcl.introduction.recoll">
<title>Recoll overview</title>
<para>&RCL; uses the
<ulink url="http://www.xapian.org">&XAP;</ulink> information retrieval
library as its storage and retrieval engine. &XAP; is a very
mature package using <ulink
url="http://www.xapian.org/docs/intro_ir.html">a sophisticated
probabilistic ranking model</ulink>. &RCL; provides the interface
to get data into (indexation) and out (searching) of the system.</para>
<para>In practice, &XAP; works by remembering where terms appear
in your document files. The acquisition process is called
indexation. </para>
<para>The resulting database can be big (roughly the size of the
original document set), but it is not a document
archive. &RCL; can only display documents that still exist at
the place from which they were indexed. (Actually, there is a
way to reconstruct a document from the information in the
database, but the result is not nice, as all formatting,
punctuation and capitalisation are lost).</para>
<para>&RCL; stores all internal data in <application>Unicode
UTF-8</application> format, and it can index files with
different character sets, encodings, and languages into the same
database. It has input filters for many document types.</para>
<para>Stemming depends on the document language. &RCL; stores
the unstemmed versions of terms and uses auxiliary databases for
term expansion. It can switch stemming languages, or add a
language, without reindexing. Storing documents in different
languages in the same database is possible, and useful in
practice, but does introduce possibilities of confusion. &RCL;
makes no attempt at automatic language recognition.</para>
<para>&RCL; has many parameters which define exactly what to
index, and how to classify and decode the source
documents. These are kept in a <link
linkend="rcl.indexing.config">configuration file</link>. A
sample configuration is installed into the
<filename>.recoll</filename> subdirectory of your home
directory when you first execute a &RCL; command. The initial
configuration will index your home directory with default
parameters and should be sufficient for giving &RCL; a try,
but you may want to adjust it later.</para>
<para><link linkend="rcl.indexing.exec">Indexation</link> is started
automatically the first time you execute the
<command>recoll</command> search graphical user interface, or by
executing the <command>recollindex</command> command.</para>
<para><link linkend="rcl.search">Searches</link> are
performed inside the <command>recoll</command>
program, which has many options to help you find what you are
looking for.</para>
</sect1>
</chapter>
<chapter id="rcl.indexing">
<title>Indexation</title>
<sect1 id="rcl.indexing.introduction">
<title>Introduction</title>
<para>Indexation is the process by which the set of documents is
analyzed and the data entered into the database. &RCL; indexation
is normally incremental: documents will only be processed if
they have been modified. On the first execution, of course, all
documents will need processing. A full index build can be forced
later on by specifying an option to the indexation command
(<command>recollindex -z</command>).</para>
<para>&RCL; indexation takes place at discrete times. There is
currently no interface to real time file modification
monitors. The typical usage is to have a nightly indexation run
<link linkend="rcl.indexing.automat">programmed</link> into your
<command>cron</command> file.</para>
<sidebar><para>Side note: there is nothing in &RCL; and &XAP;
that would prevent interfacing with a real time file
modification monitor, but this would tend to consume significant
system resources for dubious gain, because you rarely need a
full text search to find documents you just
modified. <command>recollindex -i</command> can be used to add
individual files to the index if you want to play with this, see
the manual page.</para>
</sidebar>
<para>&RCL; knows about quite a few different document
types. The parameters for document types recognition and
processing are set in
<link linkend="rcl.indexing.config">configuration files</link>
Most file types, like HTML or word processing files, only hold
one document. Some file types, like mail folder files can hold
many individually indexed documents.
</para>
<para>&RCL; indexation processes plain text, HTML, openoffice
and e-mail files internally. Other types (ie: postscript, pdf,
ms-word, rtf) need external applications for preprocessing. The
list is in the <link
linkend="rcl.install.building.prereqs">installation</link>
section.</para>
<para>Without further configuration, &RCL; will index all
appropriate files from your home directory, with a reasonable
set of defaults, if you live in western Europe or the USA. If
your normal character set is not iso8859-1, you almost certainly
need to adjust the configuration.</para>
</sect1>
<sect1 id="rcl.indexing.config">
<title>The indexation configuration</title>
<para>The main configuration file is named
<filename>$HOME/.recoll/recoll.conf</filename> by default or
<filename>$RECOLL_CONFDIR/recoll.conf</filename> if
RECOLL_CONFDIR is set.</para>
<para>The most accurate documentation for editing the file is
given by comments inside the default file that will be created
when you first start <command>recoll</command>. If you want to
adjust the configuration before indexation, just click
<guilabel>Cancel</guilabel> when the program asks if it should
start initial indexation.</para>
<para>The configuration is also documented inside the <link
linkend="rcl.install.config.recollconf">installation chapter</link> of
this document, or in the recoll.conf(5) man page.</para>
</sect1>
<sect1 id="rcl.indexing.exec">
<title>Starting indexation</title>
<para>Indexation is performed either by the
<command>recollindex</command> program, or by the
indexation thread inside the <command>recoll</command>
program (use the <guimenu>File</guimenu> menu).
<para>If the <command>recoll</command> program finds no database
when it starts, it will automatically start indexation (except
if cancelled).</para>
<para>It is best to avoid interrupting the indexation process, as
this may sometimes leave the database in a bad state. This is
not a serious problem, as you then just need to clear
everything and restart the indexation: the database files are
normally stored in the <filename>$HOME/.recoll/xapiandb</filename>
directory,
which you can just delete if needed. Alternatively, you can
start <command>recollindex -z</command>, which will
reset the database before indexation.</para>
</sect1>
<sect1 id="rcl.indexing.automat">
<title>Using <command>cron</command> to automate
indexation</title>
<para>The most common way to set up indexation is to have a cron
task execute it every night. For example the following
<filename>crontab</filename> entry would do it every day at
3:30AM (supposing <command>recollindex</command> is in your PATH):</para>
<programlisting>30 3 * * * recollindex > /tmp/recolltrace 2>&1</programlisting>
<para>The usual command to edit your
<filename>crontab</filename> is
<userinput>crontab -e</userinput> (which will usually start the
<command>vi</command> editor to edit the file). You may have
more sophisticated tools available on your system.</para>
</sect1>
</chapter>
<chapter id="rcl.search">
<title>Search</title>
<para>The <command>recoll</command> program provides the user
interface for searching. It is based on the
<application>QT</application> library.</para>
<sect1 id="rcl.search.simple">
<title>Simple search</title>
<procedure>
<step><para>Start the <command>recoll</command> program.</para>
</step>
<step><para>Enter search term(s) in the text field at the top of the
window.</para>
</step>
<step><para>Click the <guilabel>Search</guilabel> button or
hit the <keycap>Enter</keycap> key to start the search.</para>
</step>
</procedure>
<para>By default, this will look for documents with any of the
search terms (the ones with more terms will get better scores). You can
check the <guilabel>All terms</guilabel> checkbox to ensure
that only documents with all the terms will be returned. Use
the <guilabel>Tools</guilabel> / <guilabel>Advanced
search</guilabel> dialog for more complex searches.</para>
<para>After starting a search, a list of results will instantly
be displayed in the main list window. Clicking on an entry will
open an internal preview window for the
document. Double-clicking will attempt to start an external
viewer (have a look at the
<filename>~/.recoll/mimeconf</filename> file to see how these
are configured).</para>
<para>By default, the document list is presented in order of
relevance (how well the system estimates that the document
matches the query). You can specify a different ordering by
using the <link linkend="rcl.search.sort"><guilabel>Tools</guilabel>
/ <guilabel>Sort parameters</guilabel></link> dialog.</para>
<para>You can click on the first paragraph (<literal>Query
results</literal> or <literal>No results found</literal>) in the
result list to get an exact display of the query actually
performed, after stem expansion and other processing.</para>
</sect1>
<sect1 id="rcl.search.complex">
<title>Complex/advanced search</title>
<para>The advanced search dialog has fields that will allow a more
refined search, looking for documents with all given words, a
given exact phrase, or none of the given words (all relevant fields
will be combined by an implicit AND clause).</para>
<para>It will let you search for documents of specific mime
types (ie: only <literal>text/plain</literal>, or
<literal>text/html</literal> or
<literal>application/pdf</literal> etc...)</para>
<para>It will let you restrict the search results to a subtree of
the indexed area.</para>
<para>Click on the <guilabel>Start Search</guilabel> button in
the advanced search dialog to start the search. The button in
the main window always performs a simple search.</para>
<para>Click on the result list header paragraph to see the query
expansion.</para>
</sect1>
<sect1 id="rcl.search.history">
<title>Document history</title>
<para>Documents that you actually view (with the internal preview
or an external tool) are entered into the document history,
which is remembered. You can display the history list by using
the <guilabel>Tools/</guilabel><guilabel>Doc History</guilabel> menu
entry.</para>
</sect1>
<sect1 id="rcl.search.sort">
<title>Result list sorting</title>
<para>The documents in a result list are normally sorted in
order of relevance. It is possible to specify different sort
parameters by using the <guimenu>Sort parameters</guimenu>
dialog (located in the <guimenu>Tools</guimenu>
menu).</para>
<para>The tool sorts a specified number of the most
relevant documents in the result list, according to
specified criteria. The currently available criteria are
<emphasis>date</emphasis> and <emphasis>mime type</emphasis>.</para>
<para>The sort parameters stay in effect until they are explicitely
reset, or the program exits.</para>
</sect1>
<sect1 id="rcl.search.tips">
<title>Search tips, shortcuts</title>
<formalpara><title>Disabling stem expansion</title>
<para>Entering a capitalized word in any search field will prevent
stem expansion (no search for
<literal>gardening</literal> if you enter
<literal>Garden</literal> instead of
<literal>garden</literal>). This is the only case where
character case should make a difference for a &RCL;
search.</para>
</formalpara>
<formalpara><title>Phrases</title>
<para>A phrase can be looked for by enclosing it in double
quotes. Example: <literal>"user manual"</literal> will look
only for occurrences of <literal>user</literal> immediately
followed by <literal>manual</literal>. You can use the
<guilabel>This exact phrase</guilabel> field of the advanced
search dialog to the same effect.</para>
</formalpara>
<formalpara><title>Query explanation</title>
<para>You can get an exact description of what the query
looked for, including stem expansion, and boolean operators
used, by clicking on the result list header.</para>
</formalpara>
<formalpara><title>File names</title>
<para>All file name elements (the broken up file path) are entered
as terms during indexation, and you can specify them when
searching.</para>
</formalpara>
<formalpara><title>Quitting</title>
<para>Entering <keycap>^Q</keycap> almost anywhere will
close the application.</para>
</formalpara>
<formalpara><title>Closing previews</title>
<para>Entering <keycap>^W</keycap> in a preview tab will
close it (and, for the last tab, close the preview
window).</para>
</formalpara>
</sect1>
<sect1 id="rcl.search.custom">
<title>Customising the search interface</title>
<para>It is possible to customise some aspects of the search
interface by using <guimenu>Query configuration</guimenu> entry
in the <guimenu>Preferences</guimenu> menu.</para>
<para>There are two tabs in the dialog, dealing with the
interface itself, and with the parameters used for searching and
returning results.</para>
<para>User interface parameters:</para>
<itemizedlist>
<listitem><para><guilabel>Number of results in a result
page</guilabel></para>
</listitem>
<listitem><para><guilabel>Result list font</guilabel>: There
is quite a lot of information shown in the result list, and
you may want to customise the font and/or font size. The rest
of the fonts used by &RCL; are determined by your generic QT
config (try the <command>qtconfig</command> command.</para>
</listitem>
<listitem><para><guilabel>Html help browser</guilabel>: this
will let you chose your the preferred browser which will be
started from the <guimenu>Help</guimenu> menu to read the user
manual. You can enter a simple name if the command is in your
PATH, or browse for a full pathname.</para>
</listitem>
<listitem><para><guilabel>Show document type icons in result
list</guilabel>: icons in the result list can be turned
off. They take quite a lot of space and convey relatively
little useful information.</para>
</listitem>
</itemizedlist>
<para>Search parameters:</para>
<itemizedlist>
<listitem><para><guilabel>Stemming language</guilabel>:
stemming obviously depends on the document's language. This
listbox will let you chose among the stemming databases which
were built during indexing (this is set in the <link
linkend="rcl.install.config.recollconf">main configuration
file</link>), or later added with
<command>recollindex -s</command> (See the recollindex
manual). Stemming languages which are dynamically added will be
deleted at the next indexation pass unless they are also added in
the configuration file.</para>
</listitem>
<listitem><para><guilabel>Dynamically build
abstracts</guilabel>: this decides if &RCL; tries to build
document abstracts when displaying the result list. Abstracts
are constructed by taking context from the document
information, around the search terms. This can slow down
result list display significantly for big documents, and you
may want to turn it off.</para>
</listitem>
<listitem><para><guilabel>Replace abstracts from
documents</guilabel>: this decides if we should synthetize and
display an abstract in place of an explicit abstract found
within the document itself.</para>
</listitem>
</itemizedlist>
</sect1>
</chapter>
<chapter id="rcl.install">
<title>Installation</title>
<sect1 id="rcl.install.building">
<title>Building from source</title>
<sect2 id="rcl.install.building.prereqs">
<title>Prerequisites</title>
<para>At the very least, you will need to download and install the
<ulink url="http://www.xapian.org">xapian core package</ulink>
(&RCL; currently uses version 0.9.2), and the <ulink
url="http://www.trolltech.com/products/qt/index.html">qt
runtime and development packages</ulink> (&RCL; development
currently uses version 3.3.5, but any 3.3 version is
probably ok).</para>
<para>You will most probably be able to find a binary package for
<application>qt</application> for your system. You may have to
compile &XAP; but this is not difficult (if you are using
<application>FreeBSD</application>, there is a port).</para>
<para>You may also need
<ulink
url="http://www.gnu.org/software/libiconv/">libiconv</ulink>. &RCL;
currently uses version 1.9 (this should not be critical). On
<application>Linux</application> systems, the iconv interface
is part of libc and you should not need to do anything
special.</para>
<formalpara><title>External file types</title><para>&RCL; uses
external applications
to index some file types. You need to install them for the
file types that you wish to have indexed:</para>
</formalpara>
<itemizedlist>
<listitem><para>MS Word: <ulink
url="http://www.winfield.demon.nl">
antiword</ulink>.</para>
</listitem>
<listitem><para>PDF: pdftotext is part of the <ulink
url="http://www.foolabs.com/xpdf/">Xpdf</ulink> package.</para>
</listitem>
<listitem><para>Postscript: <ulink
url="http://www.cs.wisc.edu/~ghost/doc/pstotext.htm">
pstotext</ulink>.</para>
</listitem>
<listitem>
<para>RTF: <ulink
url="http://www.gnu.org/software/unrtf/unrtf.html">unrtf</ulink>
</para>
</listitem>
</itemizedlist>
<sect2 id="rcl.install.building.build">
<title>Building</title>
<para>&RCL; has been built on
Linux (redhat7.3, mandriva 2005, Fedora Core 3), FreeBSD and
Solaris 8. If you build on another system, <ulink
url="mailto:jean-francois.dockes@wanadoo.fr">I would very much
welcome patches</ulink>.</para>
<para>Depending on the <application>qt</application>
configuration on your system, you may have to set the
<literal>QTDIR</literal> and <literal>QMAKESPECS</literal>
variables in your environment:</para>
<itemizedlist>
<listitem><para><literal>QTDIR</literal> should point to the
directory above the one that holds the qt include files (ie:
qt.h).</para>
</listitem>
<listitem><para><literal>QMAKESPECS</literal> should
be set to the name of one of the
<application>qt</application> mkspecs subdirectories (ie:
linux-g++).</para>
</listitem>
</itemizedlist>
<para>On many Linux systems, <literal>QTDIR</literal> is set
by the login scripts, and <literal>QMAKESPECS</literal> is not
needed because there is a <filename>default</filename> link in
<filename>mkspecs/</filename>.</para>
<para>The &RCL; <command>configure</command> script does a
better job of checking these variables after release
1.1.1. Before this, unexplained errors will occur during
compilation if the environment is not set up. Also, for 1.1.0 the
<command>qmake</command> command should be in your PATH (later
releases can also find it in
<filename>$QTDIR/bin</filename>).</para>
<para>Normal procedure:</para>
<screen>
<userinput>cd recoll-xxx</userinput>
<userinput>configure</userinput>
<userinput>make</userinput>
<userinput>(practises usual hardship-repelling invocations)</userinput>
</screen>
<para>There little autoconfiguration. The
<command>configure</command> script will mainly link one of
the system-specific files in the <filename>mk</filename>
directory to <filename>mk/sysconf</filename>. If your system
is not known yet, it will tell you as much, and you may want
to manually copy and modify one of the existing files (the new
file name should be the output of <command>uname -s</command>).</para>
</sect2>
<sect2 id="rcl.install.building.install">
<title>Installation</title>
<para>Either type <userinput>make install</userinput> or execute
<userinput>recollinstall
<replaceable>prefix</replaceable></userinput>, in the root
of the source tree. This will copy the commands to
<filename><replaceable>prefix</replaceable>/bin</filename>
and the sample configuration files, scripts and other shared
data to
<filename><replaceable>prefix</replaceable>/share/recoll</filename>.</para>
<para>You can then proceed to <link
linkend="rcl.install.config">configuration</link>. </para>
</sect2>
</sect1>
<sect1 id="rcl.install.binary">
<title>Installing a prebuilt copy</title>
<sect2 id="rcl.install.binary.package">
<title>Installing through a package system</title>
<para>If you are lucky enough to be using a port system or a
prebuilt package (RPM or other), just follow the usual
procedure, and have a look at the <link
linkend="rcl.install.config">configuration
section</link>.</para>
</sect2>
<sect2 id="rcl.install.binary.rcl">
<title>Installing a prebuilt &RCL;</title>
<para>The unpackaged binary versions are just compressed tar
files of a build
tree, where only the useful parts were kept (executables and
sample configuration).</para>
<para>The executable binary files are built with a static link to
libxapian and libiconv, to make installation easier (no
dependencies). However, this also means that you cannot change
the versions which are used.</para>
<para>After extracting the tar file, you can proceed with
<link
linkend="rcl.install.building.install">installation</link> as
if you had built the package from source.</para>
</sect2>
</sect1>
<sect1 id="rcl.install.config">
<title>Configuration overview</title>
<para>The personal configuration files and the database are
normally kept in
the <filename>.recoll</filename> directory in your home (this
can be changed with the <literal>RECOLL_CONFDIR</literal>
environment variable, and a parameter inside the main
configuration file). If this directory does not exist when
<command>recoll</command> or
<command>recollindex</command> are started, the
directory will be created and the sample configuration files will
be copied. <command>recoll</command> will give you a
chance to edit the configuration file before starting
indexation. <command>recollindex</command> will
proceed immediately.</para>
<para>Most of the parameters specific to the
<command>recoll</command> GUI are set through the
<guilabel>Preferences</guilabel> menu and stored in the
standard QT place
(<filename>$HOME/.qt/recollrc</filename>). You probably do not
want to edit this by hand.</para>
<para>For other options, &RCL; uses text configuration
files. You will have to edit them by hand for
now (there is still some hope for a GUI configuration tool
in the future). The most accurate documentation for the
configuration parameters is given by comments inside the sample
files, and we will just give a general overview here.</para>
<para>All configuration files share the same format. For
exemple, a short extract of the main configuration file might
look as follows:</para>
<programlisting>
# Space-separated list of directories to index.
topdirs = ~/docs /usr/share/doc
[~/somedirectory-with-utf8-txt-files]
defaultcharset = utf-8
</programlisting>
<para>There are three kinds of lines: </para>
<itemizedlist>
<listitem><para>Comment (starts with
<emphasis>#</emphasis>) or empty.</para>
</listitem>
<listitem><para>Parameter affectation (<emphasis>name =
value</emphasis>).</para>
</listitem>
<listitem><para>Section definition
([<emphasis>somedirname</emphasis>]).</para>
</listitem>
</itemizedlist>
<para>Section lines allow redefining some parameters for a
directory subtree. Some of the parameters used for indexation
are looked up hierarchically from the more to the less
specific. Not all parameters can be meaningfully redefined,
this is specified for each in the next section. </para>
<para>The tilde character (~) is expanded in file names to the
name of the user's home directory.</para>
<para>White space is used for separation inside lists.
Elements with embedded spaces can be quoted using
double-quotes.</para>
<sect2 id="rcl.install.config.recollconf">
<title>Main configuration file</title>
<para><filename>~/.recoll/recoll.conf</filename> is the main
configuration file. It defines things like
what to index (top directories and things to ignore), and the
default character set to use for document types which do not
specify it internally. </para>
<para>The default configuration will index your home
directory. If this is not appropriate, use
<command>recoll</command> to copy the sample
configuration, click <guimenu>Cancel</guimenu>, and edit
the configuration file before restarting the command. This
will start the initial indexation, which may take some time.</para>
<para>Paramers:</para>
<variablelist>
<varlistentry><term><literal>topdirs</literal></term>
<listitem><para>Specifies the list of directories to index
(recursively).</para>
</listitem>
</varlistentry>
<varlistentry><term><literal>skippedNames</literal></term>
<listitem>
<para>A space-separated list of patterns for
names of files or directories that should be completely
ignored. The list defined in the default file is: </para>
<programlisting>
*~ #* bin CVS Cache caughtspam tmp
</programlisting>
<para>The list can be redefined for subdirectories, but is only
actually changed for the top level ones in
<literal>topdirs</literal>.</para>
<para>The top-level directories are not affected by this
list (that is, a directory in <literal>topdirs</literal>
might match and would still be indexed).</para>
<para>The list in the default configuration does not
exclude hidden directories (names beginning with a
dot), which means that it may index quite a few things
that you do not want. On the other hand, mail user
agents like <application>thunderbird</application>
usually store messages in hidden directories, and you
probably want this indexed. One possible solution is to
have <userinput>.*</userinput> in
<literal>skippedNames</literal>, and add things like
<filename>~/.thunderbird</filename> or
<filename>~/.evolution</filename> in
<literal>topdirs</literal>.</para>
</listitem>
</varlistentry>
<varlistentry><term><literal>loglevel</literal></term>
<listitem><para>Verbosity level for recoll and
recollindex. A value of 4 lists quite a lot of
debug/information messages. 2 only lists errors. </para>
</listitem>
</varlistentry>
<varlistentry><term><literal>logfilename</literal></term>
<listitem><para>Where should the messages go. 'stderr' can
be used as a special value. </para>
</listitem>
</varlistentry>
<varlistentry><term><literal>filtersdir</literal></term>
<listitem><para>A directory to search for the external
filter scripts used to index some types of files. The
value should not be changed, except if you want to modify
one of the default scripts. The value can be redefined for
any subdirectory. </para>
</listitem>
</varlistentry>
<varlistentry><term><literal>indexstemminglanguages</literal></term>
<listitem><para>A list of languages for which the stem
expansion databases will be built. See recollindex(1) for
possible values. You can add a stem expansion database for
a different language by using <command>recollindex
-s</command>, but it will be deleted during the next
indexation. Only languages listed in the configuration
file are permanent.</para>
</listitem>
</varlistentry>
<varlistentry><term><literal>iconsdir</literal></term>
<listitem><para>The name of the directory where
<command>recoll</command> result list icons are
stored. You can change this if you want different
images.</para>
</listitem>
</varlistentry>
<varlistentry><term><literal>dbdir</literal></term>
<listitem><para>The name of the Xapian database
directory. It will be created if needed when the database
is initialized. </para>
</listitem>
</varlistentry>
<varlistentry><term><literal>defaultcharset</literal></term>
<listitem><para>The name of the character set used for
files that do not contain a character set definition (ie:
plain text files). This can be redefined for any
subdirectory.</para>
<varlistentry><term><literal>guesscharset</literal></term>
<listitem><para>Decide if we try to guess the character
set of files if no internal value is available (ie: for
plain text files). This does not work well in general, and
should probably not be used. </para>
</listitem>
</varlistentry>
<varlistentry><term><literal>usesystemfilecommand</literal></term>
<listitem><para>Decide if we use the <command>file -i</command>
system command as a final step for determining the mime
type for a file (the main procedure uses suffix
associations as defined in the <filename>mimemap</filename>
file). This can be useful for files with suffixless names,
but it will also cause the indexation of many bogus "text"
files.</para>
</listitem>
</varlistentry>
</variablelist>
</sect2>
<sect2 id="rclinstall.config.mimemap">
<title>The mimemap file</title>
<para><filename>~/.recoll/mimemap</filename> specifies the
file name extension to mime type mappings.</para> <para>For
file names without an extension, or with an unknown one, the
system's <command>file -i</command> command will be executed
to determine the mime type (this can be switched off inside
the main configuration file).</para>
<para><filename>mimemap</filename> also has a list of
extensions which should be ignored totally (to avoid losing
time by executing <command>file</command>
for things that certainly should not be indexed).</para>
<para>The mappings can be specified on a per-subtree basis,
which may be useful in some cases. Example:
<application>gaim</application> logs have a
<filename>.txt</filename> extension but
should be handled specially, which is possible because they
are usually all located in one place.</para>
<para><filename>mimemap</filename> also has a
<literal>recoll_noindex</literal> variable which is a list of
suffixes. Matching files will be skipped (avoids unnecessary
decompressions or <command>file</command> executions). This is
partially redundant with <literal>skippedNames</literal> in
the main configuration file, with two differences: it will not
affect directories, and it can be changed for any
subdirectory.</para>
</sect2>
<sect2 id="rclinstall.config.mimeconf">
<title>The mimeconf file</title>
<para><filename>~/.recoll/mimeconf</filename> specifies how the
different mime types are handled for indexation, and for
display.</para>
<para>Changing the indexation parameters is probably not a
good idea except if you are a &RCL; developper.</para>
<para>You may want to adjust the external viewers defined in
(ie: html is either
previewed internally or displayed using
<application>firefox</application>, but you may prefer
<application>mozilla</application>...). Look for the
<literal>[view]</literal> section.</para>
<para>You can also change the icons which are displayed by
<command>recoll</command> in the result lists (the values are
the basenames of the png images inside the
<filename>iconsdir</filename> directory (specified in
<filename>recoll.conf</filename>).</para>
</sect2>
</sect1>
</chapter>
</book>