# Fast Similar Files Finder

## Basics

### Info

findsimilars walks along the given dirs to find all similar files.

### Description

findsimilars will find all similar files, not only identical ones: different version (.txt, .html, or .pdf) and different compression methods (.zip, .gz, .tar.gz, .bip2), MP3 files with slightly different names or even different sample rates, etc. It uses advanced soundex vector algorithm to determine the file similarities.

The file similarity checking is extremely fast. It uses advanced soundex vector algorithm to determine the similarity between files. Generally it means that if there are n files, each having approximately m words in the file name, the degree of calculation is merely

    O(n^2 * m)

regardless of file size. This is over hundreds times faster than any existing file fingerprinting technology.

### Files

Release notes.

Changes logs.

## Help

The self-test output will help you understand what the module do and what would you expect from the outcome.

    $ make test
    PERL_DL_NONLAZY=1 /usr/bin/perl "-Iblib/lib" "-Iblib/arch" test.pl
    1..5 todo 2;
    # Running under perl version 5.010000 for linux
    # Current time local: Mon Nov  3 08:57:42 2008
    # Current time GMT:   Mon Nov  3 13:57:42 2008
    # Using Test.pm version 1.25
    # Testing File::FindSimilars version 2.03

1. . .

#### Testing 2, files under test/ subdir:

      9 test/(eBook) GNU - Python Standard Library 2001.pdf
      3 test/Audio Book - The Grey Coloured Bunnie.mp3
      5 test/ColoredGrayBunny.ogg
      5 test/GNU - 2001 - Python Standard Library.pdf
      4 test/GNU - Python Standard Library (2001).rar
      9 test/LayoutTest.java
      3 test/PopupTest.java
      2 test/Python Standard Library.zip
    ok 2 # (test.pl at line 83 TODO?!)

Note:

- The findsimilars script will pick out similar files from them in next test.

- Let's assume that the number represent the file size in KB.

#### Testing 3 result should be:

    ## =========
               3 'Audio Book - The Grey Coloured Bunnie.mp3' 'test/'
               5 'ColoredGrayBunny.ogg'                      'test/'

    ## =========
               4 'GNU - Python Standard Library (2001).rar' 'test/'
               5 'GNU - 2001 - Python Standard Library.pdf' 'test/'
    ok 3

Note:

- There are 2 groups of similar files picked out by the script.

- The similar files are picked because their file names look similar. Note that the first group looks different and spells differently too, which means that the script is versatile enough to handle file names that don't have space in it, and robust enough to deal with spelling mistakes.

- Apart from the file name, the file size plays an important role as well.

- There are 2 files in the second similar files group, the book files group.

- The file Python Standard Library.zip is not considered to be similar to the group because its size is not similar to the group.

#### Testing 4, if Python.zip is bigger, result should be:

    ## =========
               4 'Python Standard Library.zip' 'test/'
               4 'GNU - Python Standard Library (2001).rar' 'test/'
               5 'GNU - 2001 - Python Standard Library.pdf' 'test/'

    ## =========
               3 'Audio Book - The Grey Coloured Bunnie.mp3' 'test/'
               5 'ColoredGrayBunny.ogg'                      'test/'
    ok 4

Note:

- The previous second similar files group is now the first. I.e., the order of similar files groups is not important.

- There are now 3 files in the book files group.

- The file Python Standard Library.zip is included in the group because its size is now similar to the group.

#### Testing 5, if Python.zip is even bigger, result should be:

    ## =========
               4 'GNU - Python Standard Library (2001).rar' 'test/'
               5 'GNU - 2001 - Python Standard Library.pdf' 'test/'
               6 'Python Standard Library.zip' 'test/'
               9 '(eBook) GNU - Python Standard Library 2001.pdf' 'test/'

    ## =========
               3 'Audio Book - The Grey Coloured Bunnie.mp3' 'test/'
               5 'ColoredGrayBunny.ogg'                      'test/'
    ok 5

Note:

- There are 4 files in the book files group now.

- The file Python Standard Library.zip is still in the group.

- But this time, because it is also considered to be similar to the .pdf file (since their size are now similar, 6 vs 9), a 4th file the .pdf one is now included in the book group.

- If the size of file Python Standard Library.zip is 12(KB), then the book files group will be split into two. Do you know why and which files each group will contain?

## Installation & Configuration

### Installation

    perl Makefile.PL
    make
    make test
    make install

There includes in the package a client program called findsimilars. It should have been copied to a directory which is in the PATH by make install.

### Get Help

Issue findsimilars to get help on how to use it. And also,

    perldoc File::FindSimilars

## Misc

Why writting such tool; why it might be necessary.