Basic format for command 'service':
    vitis-sl service <subcommand> <data> [options]

The command is used to configure vitis-sl and retrieve service information.
By default, the settings are stored in the file '~/vitis-sl/.vitis-sl.conf', but each time
you call vitis-sl, you can use an alternate configuration file
using option '--conf=<path_to_configure_file>'.

Subcommands 'add', 'get', 'set' allow to work with the vitis-sl settings.
The configuration elements currently are:
    path               - path where vitis-sl stores categories and links to files;
    lang               - used language (auto, en_US, eo, ru_RU);
    filespace(s)       - paths to directories of file spaces in the file system;
    autosave           - automatic save to file space;
    opener             - program selected for universal opening of files;
    casesensitivity    - case sensitivity for categories;
    autocategorization - mode of automatic categories;
    default            - parameters by default (only for the set command).

    vitis-sl service set path <my_path>
        Sets the path to the root directory of vitis-sl.
        Example:
            vitis-sl service set path /data/local/vitis-slDir

    vitis-sl service get path
        Displays the path to the root directory of vitis-sl.
        By default, '/home/$USERNAME/vitis-sl'.

    vitis-sl service set lang <language>
        Sets the language localization for vitis-sl.
        Example:
            vitis-sl service set lang ru_RU
        Supports 'en_US', 'ru_RU' and 'eo'. The 'auto' value is available,
        at which the language is determined by the system settings.

    vitis-sl service get lang
        Displays the language locale used, for example, ru_RU or en_US.
    
    vitis-sl service set autosave <value>
        The value can be "yes" or "no".
        With "yes", a mode is set in which new files are automatically copied
        to the first available file space.
    
    vitis-sl service get autosave
        Displays the value of the autosave option.

    vitis-sl service set opener <application>
        The user-specified program becomes a universal program
        for opening files.
        Example:
            vitis-sl service set opener mime-open

    vitis-sl service get opener
        Displays the program selected for use with the 'vitis-sl open' command.
        By default, the ufo utility is used (by-product of the vitis-sl
        project).

    vitis-sl service set casesensitivity <value>
        Sets case sensitivity of categories.
        The value can be "yes" or "no".
        Example:
            vitis-sl service set casesensitivity no

    vitis-sl service get casesensitivity
        Indicates whether vitis-sl is sensitive to the register
        in relation to categories.
        Outputs "yes" or "no".
    
    vitis-sl service set autocategorization <value>
        Sets the autocategorization mode.
        Valid values ​​are 'format', 'extension' and 'none'.
        If 'format' is set, files added to vitis-sl are automatically assigned
        categories indicating file formats.
        If 'extensionl is set, the files correspond to the categories
        denoting file extensions.
        Values ​​can be combined with a semicolon.
        By default, the autocategorization mode is set to 'format;extension'.
        The value 'none' disables autocategories.
    
    vitis-sl service get autocategorization
        Shows the current autocategorization mode.

    vitis-sl service set default
        Resets settings to default values.

The configuration parameters 'filespace' and 'filespaces' allows to assign
files to which the vitis-sl system will refer.
File spaces are used in the 'assign' command with the '--save' flag:
    vitis-sl service reset filespaces
    vitis-sl service add filespace /mnt/BigDisk/All
    vitis-sl assign -c Photo -f /my/path/image.jpg --save
        The file 'image.jpg' from '/my/path/' will be copied
        to the first available directory from the number of filespaces
        (i.e. to the directory '/mnt/BigDisk/All').
        Details:
            vitis-sl assign --help

    vitis-sl service get filespaces
        Displays a list of paths to file spaces.
        By default, the list is empty.
    
    vitis-sl service reset filespaces
        Clears the list of file spaces.

    vitis-sl service add filespace </my/path>
        Allows to add a file space.
        Example:
            vitis-sl service add filespace /mnt/BigDisk/All/

    vitis-sl service prioritize filespace </my/path>
        Puts the file space first in the list.

vitis-sl service disregard filespace </path/to/filespace>
    Removes unnecessary file space from the configuration settings.
    Example:
        vitis-sl service disregard filespace /mnt/BigDisk/All

Subcommand 'check' checks the state of the vitis-sl system.
Format of subcommand:
    vitis-sl check <object> [-c category] [[--fix][--interactive]]
Objects of checking (options after 'check'):
    broken-links      - broken symbolic links;
    saved-pages       - presence of saved pages to network bookmarks;
    fileformats       - checking that all files have the correct automatic
                        categories indicating file formats.

Option '--fix' fixes invalid situations.
Option '-c' allows to specify the category by which the check will be performed.
    If you do not use the '-c' option,
    the test is performed throughout the vitis-sl system.
Option '--interactive' is a compromise between simple diagnostics
    and automatic fixing of problems. User independently makes a decision
    on each case during the diagnostics.
    It cancels the '--fix' option.
Option '--fresh' is only available for option 'saved-pages',
    it allows to update local copies of previously save pages.

Examples:

    vitis-sl check broken-links
        It will search for the broken links, the result of the diagnostics
        will be displayed in the terminal for the possibility of correction.

    vitis-sl check broken-links --fix
        All broken links will be deleted.

    vitis-sl check broken-links -c Музыка --interactive
        Diagnostics for the presence of broken links in the category 'Music'.
        For each such link the user is asked to delete.

    vitis-sl check saved-pages
        Passes through the contents of the automatic category
        'NetworkBookmarks',
        displays information about which pages were not saved locally.

    vitis-sl check saved-pages --fix
        Local copies of the pages will be saved
        for all bookmarks those did not have them.

    vitis-sl check saved-pages --fresh
        Previously created local copies will be updated.

    vitis-sl check saved-pages --fix --fresh
        All net-bookmarks will receive updated copies of the pages.

    vitis-sl check fileformats -c "Computer Science"
        A check is made for the exposure and correctness of automatic categories
        denoting file formats for the category "Computer Science".
    
