NAME
    Dir::Split - Split files of a directory to subdirectories

SYNOPSIS
     use Dir::Split;

     # example arguments
     $dir = Dir::Split->new(
         mode    =>    'num',

         source  =>    '/source',
         target  =>    '/target',

         verbose     =>        1,
         override    =>        0,

         identifier  =>    'sub',
         file_limit  =>        2,
         file_sort   =>      '+',

         separator   =>      '-',
         continue    =>        1,
         length      =>        5,
     );

     $retval = $dir->split_dir;

DESCRIPTION
    "Dir::Split" moves files to either numbered or characteristic
    subdirectories.

  numeric splitting
    Numeric splitting is an attempt to gather files from a source directory
    and split them to numbered subdirectories within a target directory. Its
    purpose is to automate the archiving of a great amount of files, that
    are likely to be indexed by numbers.

  characteristic splitting
    Characteristic splitting allows indexing by using leading characters of
    filenames. While numeric splitting is being characterised by dividing
    file amounts, characteristic splitting tries to keep up the contentual
    recognition of data.

CONSTRUCTOR
  new
    Creates a new "Dir::Split" object.

     # example arguments
     $dir = Dir::Split->new(
         mode    =>    'num',

         source  =>    '/source',
         target  =>    '/target',

         verbose     =>        1,
         override    =>        0,

         identifier  =>    'sub',
         file_limit  =>        2,
         file_sort   =>      '+',

         separator   =>      '-',
         continue    =>        1,
         length      =>        5,
     );

     $dir = Dir::Split->new(%args);

METHODS
  split_dir
    Splits files to subdirectories.

     $retval = $dir->split_dir;

    Checking the return value will provide further insight, what action
    split_dir() has taken. See (OPTIONS / debug) on how to become aware of
    errors.

   Return Values
      1 / $ACTION           Files splitted

      0 / $NOACTION         No action

     -1 / $EXISTS           Files exist
                            (see OPTIONS / debug)

     -2 / $FAILURE          Failure
                            (see OPTIONS / debug)

ARGUMENTS
  numeric
    Split files to subdirectories with a numeric suffix.

     %args = (
         mode    =>    'num',

         source  =>    '/source',
         target  =>    '/target',

         verbose     =>        1,
         override    =>        0,

         identifier  =>    'sub',
         file_limit  =>        2,
         file_sort   =>      '+',

         separator   =>      '-',
         continue    =>        1,
         length      =>        5,
     );

    * "mode"
        *num* for numeric.

    * "source"
        source directory.

    * "target"
        target directory.

    * "verbose"
        if enabled, mkpath will output the paths on creating subdirectories.

         MODES
           1  enabled
           0  disabled

    * "override"
        overriding of existing files.

         MODES
           1  enabled
           0  disabled

    * "identifier"
        prefix of each subdirectory created.

    * "file_limit"
        limit of files per subdirectory.

    * "file_sort"
        sort order of files.

         MODES
           +  ascending
           -  descending

    * "separator"
        suffix separator.

    * "continue"
        numbering continuation.

         MODES
           1  enabled
           0  disabled    (will start at 1)

        If numbering continuation is enabled, and numbered subdirectories
        are found within target directory which match the given identifier
        and separator, then the suffix numbering will be continued.
        Disabling numbering continuation may interfere with existing files /
        directories.

    * "length"
        character length of the suffix.

        This option will have no effect, if its smaller in length than the
        current length of the highest suffix number.

  characteristic
    Split files to subdirectories with a characteristic suffix. Files are
    assigned to subdirectories which suffixes equal the specified, leading
    character(s) of the filenames.

     %args = (
         mode    =>    'char',

         source  =>    '/source',
         target  =>    '/target',

         verbose     =>         1,
         override    =>         0,

         identifier  =>     'sub',

         separator   =>       '-',
         case        =>   'upper',
         length      =>         1,
     );

    * "mode"
        *char* for characteristic.

    * "source"
        source directory.

    * "target"
        target directory.

    * "verbose"
        if enabled, mkpath will output the pathes on creating
        subdirectories.

         MODES
           1  enabled
           0  disabled

    * "override"
        overriding of existing files.

         MODES
           1  enabled
           0  disabled

    * "identifier"
        prefix of each subdirectory created.

    * "separator"
        suffix separator.

    * "case"
        lower / upper case of the suffix.

         MODES
           lower
           upper

    * "length"
        character length of the suffix.

        < 4 is highly recommended (26 (alphabet) ^ 3 == 17'576 suffix
        possibilites). "Dir::Split" will not prevent using suffix lengths
        greater than 3. Imagine splitting 1'000 files and using a character
        length > 20. The file rate per subdirectory will almost certainly
        approximate 1/1 - which equals 1'000 subdirectories.

        Whitespaces in suffixes will be removed.

OPTIONS
  Tracking
    %Dir::Split::track keeps count of how many files the source and
    directories / files the target consists of. It may be useful, if the
    amount of files that could not be transferred due to existing ones, has
    to be counted. Each time a new splitting is attempted, the track will be
    reseted.

     %Dir::Split::track = (
         source  =>    {  files  =>    512
         },
         target  =>    {  dirs   =>    128,
                          files  =>    512,
         },
     );

    Above example: directory consisting of 512 files successfully splitted
    to 128 directories.

  Debug
    Existing

    If "split_dir()" returns $EXISTS, this implys that the override option
    is disabled and files weren't moved due to existing files within the
    target subdirectories; they will have their paths appearing in
    @Dir::Split::exists.

     file    @Dir::Split::exists    # Existing files, not attempted to
                                    # be overwritten.

    Failures

    If "split_dir()" returns $FAILURE, this most often implys that the
    override option is enabled and existing files could not be overwritten.
    Files that could not be copied / unlinked, will have their paths
    appearing in the according keys in %Dir::Split::failure.

     file    @{$Dir::Split::failure{copy}}      # Files that couldn't be copied,
                                                # most often on overriding failures.

             @{$Dir::Split::failure{unlink}}    # Files that could be copied but not unlinked,
                                                # rather seldom.

    It is recommended to evaluate those arrays on $FAILURE.

    A @Dir::Split::exists array may coexist.

  Unlinking
    Files in a flat source directory may be unlinked by setting:

     # Unlink files in flat source
     $Dir::Split::UNLINK = 1;

  Traversing
    Traversal processing of files may be activated by setting:

     # Traversal mode
     $Dir::Split::TRAVERSE = 1;

    No depth limit e.g. all underlying directories / files will be
    evaluated.

    Options

     # Unlink files in source
     $Dir::Split::TRAVERSE_UNLINK = 1;

    Unlinks files after they have been moved to their new locations.

     # Remove directories in source
     $Dir::Split::TRAVERSE_RMDIR = 1;

    Removes the directories in source, after the files have been moved. In
    order to take effect, this option requires the
    $Dir::Split::TRAVERSE_UNLINK to be set.

     # Remove the source directory itself
     $Dir::Split::TRAVERSE_RMDIR_SOURCE = 1;

    It is not recommended to turn on the latter options
    $Dir::Split::TRAVERSE_UNLINK, $Dir::Split::TRAVERSE_RMDIR and
    $Dir::Split::TRAVERSE_RMDIR_SOURCE, unless one is aware of the
    consequences they imply.

EXAMPLES
    Assuming the source directory contains these files:

     +- _123
     +- abcd
     +- efgh
     +- ijkl
     +- mnop

    After splitting the source directory tree to the target, it would result
    in:

  numeric splitting
     +- sub-00001
     +-- _123
     +-- abcd
     +- sub-00002
     +-- efgh
     +-- ijkl
     +- sub-00003
     +-- mnop

  characteristic splitting
     +- sub-_
     +-- _123
     +- sub-a
     +-- abcd
     +- sub-e
     +-- efgh
     +- sub-i
     +-- ijkl
     +- sub-m
     +-- mnop

SEE ALSO
    File::Basename, File::Copy, File::Find, File::Path, File::Spec

AUTHOR
    Steven Schubiger <schubiger@cpan.org>

LICENSE
    This program is free software; you may redistribute it and/or modify it
    under the same terms as Perl itself.

    See <http://www.perl.com/perl/misc/Artistic.html>

