4.4. Configuration overview

Most of the parameters specific to the recoll GUI are set through the Preferences menu and stored in the standard QT place ($HOME/.qt/recollrc). You probably do not want to edit this by hand.

For other options, Recoll 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 default files, and we will just give a general overview here.

There are two sets of configuration files. The system-wide files are kept in a directory named like /usr/[local/]share/recoll/examples, they define default values for the system. A parallel set of files exists by default in the .recoll directory in your home. This directory can be changed with the RECOLL_CONFDIR environment variable or the -c option parameter to recoll and recollindex.

If the .recoll directory does not exist when recoll or recollindex are started, it will be created with a set of empty configuration files. recoll will give you a chance to edit the configuration file before starting indexing. recollindex will proceed immediately. To avoid mistakes, the automatic directory creation will only occur for the default location, not if -c or RECOLL_CONFDIR were used (in the latter cases, you will have to create the directory).

All configuration files share the same format. For example, a short extract of the main configuration file might look as follows:

        # Space-separated list of directories to index.
        topdirs =  ~/docs /usr/share/doc

        [~/somedirectory-with-utf8-txt-files]
        defaultcharset = utf-8
       

There are three kinds of lines:

Section definitions allow redefining some parameters for a directory sub-tree. They stay in effect until another section definition, or the end of file, is encountered. Some of the parameters used for indexing are looked up hierarchically from the current directory location upwards. Not all parameters can be meaningfully redefined, this is specified for each in the next section.

When found at the beginning of a file path, the tilde character (~) is expanded to the name of the user's home directory, as a shell would do.

White space is used for separation inside lists. List elements with embedded spaces can be quoted using double-quotes.

4.4.1. Main configuration file

recoll.conf 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.

The default configuration will index your home directory. If this is not appropriate, start recoll to create a blank configuration, click Cancel, and edit the configuration file before restarting the command. This will start the initial indexing, which may take some time.

Paramers:

topdirs

Specifies the list of directories or files to index (recursively for directories). The indexer will not follow symbolic links inside the indexed trees by default (see the followLinks options though).

dbdir

The name of the Xapian data directory. It will be created if needed when the index is initialized. If this is not an absolute path, it will be interpreted relative to the configuration directory. The value can have embedded spaces but starting or trailing spaces will be trimmed. You cannot use quotes here.

skippedNames

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:

skippedNames = #* bin CVS  Cache cache* caughtspam  tmp .thumbnails .svn \
         *~ recollrc

The list can be redefined for sub-directories, but is only actually changed for the top level ones in topdirs.

The top-level directories are not affected by this list (that is, a directory in topdirs might match and would still be indexed).

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 thunderbird usually store messages in hidden directories, and you probably want this indexed. One possible solution is to have .* in skippedNames, and add things like ~/.thunderbird or ~/.evolution in topdirs.

skippedPaths and daemSkippedPaths

A space-separated list of patterns for paths of files or directories that should be skipped. There is no default in the sample configuration file, but the code always adds the configuration and database directories in there.

skippedPaths is used both by batch and real time indexing. daemSkippedPaths can be used to specify things that should be indexed at startup, but not monitored.

Example of use for skipping text files only in a specific directory:

skippedPaths = ~/somedir/*.txt
             
followLinks

Specifies if the indexer should follow symbolic links while walking the file tree. The default is to ignore symbolic links to avoid multiple indexing of linked files. No effort is made to avoid duplication when this option is set to true. This option can be set individually for each of the topdirs members by using sections. It can not be changed below the topdirs level.

loglevel,daemloglevel

Verbosity level for recoll and recollindex. A value of 4 lists quite a lot of debug/information messages. 2 only lists errors. The daemversion is specific to the indexing monitor daemon.

logfilename, daemlogfilename

Where the messages should go. 'stderr' can be used as a special value, and is the default. The daemversion is specific to the indexing monitor daemon.

indexstemminglanguages

A list of languages for which the stem expansion databases will be built. See recollindex(1) or use the recollindex -l command for possible values. You can add a stem expansion database for a different language by using recollindex -s, but it will be deleted during the next indexing. Only languages listed in the configuration file are permanent.

defaultcharset

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 sub-directory. If it is not set at all, the character set used is the one defined by the nls environment (LC_ALL, LC_CTYPE, LANG), or iso8859-1 if nothing is set.

maxfsoccuppc

Maximum file system occupation before we stop indexing. The value is a percentage, corresponding to what the "Capacity" df output column shows. The default value is 0, meaning no checking.

idxflushmb

Threshold (megabytes of new text data) where we flush from memory to disk index. Setting this can help control memory usage. A value of 0 means no explicit flushing, letting Xapian use its own default, which is flushing every 10000 documents (memory usage depends on average document size). The default value is 10.

filtersdir

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 sub-directory.

iconsdir

The name of the directory where recoll result list icons are stored. You can change this if you want different images.

guesscharset

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.

usesystemfilecommand

Decide if we use the file -i system command as a final step for determining the mime type for a file (the main procedure uses suffix associations as defined in the mimemap file). This can be useful for files with suffix-less names, but it will also cause the indexing of many bogus "text" files.

indexallfilenames

Recoll indexes file names in a special section of the database to allow specific file names searches using wild cards. This parameter decides if file name indexing is performed only for files with mime types that would qualify them for full text indexing, or for all files inside the selected subtrees, independently of mime type.

idxabsmlen

Recoll stores an abstract for each indexed file inside the database. This is so that they can be displayed inside the result lists without decoding the original file. This parameter defines the size of the stored abstract (which can come from an actual section or just be the beginning of the text). The default value is 250.

aspellLanguage

Language definitions to use when creating the aspell dictionary. The value must match a set of aspell language definition files. You can type "aspell config" to see where these are installed (look for data-dir). The default if the variable is not set is to use your desktop national language environment to guess the value.

noaspell

If this is set, the aspell dictionary generation is turned off. Useful for cases where you don't need the functionality or when it is unusable because aspell crashes during dictionary generation.

4.4.2. The mimemap file

mimemap specifies the file name extension to mime type mappings.

For file names without an extension, or with an unknown one, the system's file -i command will be executed to determine the mime type (this can be switched off inside the main configuration file).

The mappings can be specified on a per-subtree basis, which may be useful in some cases. Example: gaim logs have a .txt extension but should be handled specially, which is possible because they are usually all located in one place.

mimemap also has a recoll_noindex variable which is a list of suffixes. Matching files will be skipped (which avoids unnecessary decompressions or file executions). This is partially redundant with skippedNames in the main configuration file, with two differences: it will not affect directories, and it cannot be made dependant on the file-system location (it is a configuration-wide parameter). You could accomplish with skippedNames anything that recoll_noindex does. The latter is used mostly for things known to be unindexable by a given Recoll version. Having it there avoids cluttering the more user-oriented and locally customized skippedNames.

4.4.3. The mimeconf file

mimeconf specifies how the different mime types are handled for indexing, and which icons are displayed in the recoll result lists.

Changing the parameters in the [index] section is probably not a good idea except if you are a Recoll developer.

The [icons] section allows you to change the icons which are displayed by recoll in the result lists (the values are the basenames of the png images inside the iconsdir directory (specified in recoll.conf).

4.4.4. The mimeview file

mimeview specifies which programs are started when you click on an Edit link in a result list. Ie: HTML is normally displayed using firefox, but you may prefer Konqueror, your openoffice.org program might be named oofice instead of openoffice etc.

Changes to this file can be done by direct editing, or through the recoll user preferences dialog.

As for the other configuration files, the normal usage is to have a mimeview inside your own configuration directory, with just the non-default entries, which will override those from the central configuration file.

Please note that these entries must be placed under a [view] section.

If Use desktop preferences to choose document editor is checked in the user preferences, all mimeview entries will be ignored except the one labelled application/x-all (which is set to use xdg-open by default).

4.4.5. Examples of configuration adjustments

4.4.5.1. Adding an external viewer for an non-indexed type

Imagine that you have some kind of file which does not have indexable content, but for which you would like to have a functional Edit link in the result list (when found by file name). The file names end in .blob and can be displayed by application blobviewer.

You need two entries in the configuration files for this to work:

  • In $RECOLL_CONFDIR/mimemap (typically ~/.recoll/mimemap), add the following line:

                 application/x-blobapp = .blob
              
    

    Note that the mime type is made up here, and you could call it diesel/oil just the same.

  • In $RECOLL_CONFDIR/mimeview under the [view] section:

                     application/x-blobapp = blobviewer %f
                 
    

    We are supposing that blobviewer wants a file name parameter here, you would use %u if it liked URLs better.

If you just wanted to change the application used by Recoll to display a mime type which it already knows, you would just need to edit mimeview. The entries you add in your personal file override those in the central configuration, which you do not need to alter

4.4.5.2. Adding indexing support for a new file type

Let us now imagine that the above .blob files actually contain indexable text and that you know how to extract it with a command line program. Getting Recoll to index the files is easy. You need to perform the above alteration, and also to add data to the mimeconf file (typically in ~/.recoll/mimeconf):

  • Under the [index] section, add the following line (more about the rclblob indexing script later):

                     application/x-blobapp = exec rclblob
                 
    
  • Under the [icons] section, you should choose an icon to be displayed for the files inside the result lists. Icons are normally 64x64 pixels PNG files which live in /usr/[local/]share/recoll/images.

  • Under the [categories] section, you should add the mime type where it makes sense (you can also create a category). Categories may be used for filtering in advanced search.

The rclblob filter should be an executable program or script which exists inside /usr/[local/]share/recoll/filters. It will be given a file name as argument and should output the text contents in html format on the standard output.

You can find more details about writing a Recoll filter in the section about writing filters