File::Canonicalizer - ASCII file canonicalizer


   use File::Canonicalizer;

   $aref = [ 'replaced_pattern1', 'replacement1',
             'replaced_pattern2', 'replacement2',
             ... ];

   file_canonicalizer ('input_file','canonical_output_file', '',4,5,6,7,8,9,10, $aref);


Sometimes files must be compared semantically, that is their contents, not their forms are to be compared. Following two files have different forms, but contain identical information:


   First name -        Barack

   Last name  -        Obama

   Birth Date -        1961/8/4

   Profession -        President 


   last name : Obama
   first name: Barack
   profession: president   # not sure

   Birth Date: 1961/08/04

Some differences between forms of these files are:

  • arbitrary line order

  • arbitrary character cases

  • arbitrary leading zeroes for numbers

  • arbitrary amounts of white characters

  • arbitrary comments

  • arbitrary empty lines

  • field separators

Using file_canonicalizer allows one to simplify both of these files, so that they can be compared with each other.



   file_canonicalizer ( <input_file>                                   # 1 default is STDIN
                      , <output_file>                                  # 2 default is STDOUT 
                      , remove_comments_started_with_<regular_express> # 3 if empty, ignore comments
                      , 'replace_adjacent_tabs_and_spaces_with_1_space'# 4
                      , 'replace_adjacent_slashes_with_single_slash'   # 5
                      , 'remove_white_characters_from_line_edges'      # 6
                      , 'remove_empty_lines'                           # 7
                      , 'convert_to_lower_cased'                       # 8
                      , 'remove_leading_zeroes_in_numbers'             # 9
                      , 'sort_lines_lexically'                         #10
                      , array_reference_to_pairs_replaced_replacement  #11

All parameters, beginning with the 3rd, are interpreted as Boolean values true or false. A corresponding action will be executed only if its parameter value is true. This means, that each of literals between apostrophes '' can be shortened to single arbitrary character or digit 1-9.

List of parameters can be shortened, that is any amount of last parameters can be skipped. In this case the actions, corresponding skipped parameters, will not be executed.


Read from STDIN, write to STDOUT and remove all substrings, beginning with '#' :

   file_canonicalizer ('','','#');

Create canonicalized cron table (on UNIX/Linux) in any of equivalent examples:

   file_canonicalizer('path/cron_table','/tmp/cron_table.canonic','#',4,5, 6,    7,       '',9, 10);
   file_canonicalizer('path/cron_table','/tmp/cron_table.canonic','#',1,1, 1,    1,       '',1, 1);

Canonicalization of files 'file_A' and 'file_B', shown in the section "DESCRIPTION":

   file_canonicalizer('file_A','file_A.canonic','#',1,5,1,1,1,1,10, ['\s*-\s*',' : ', '^','<', '$','>']);
   file_canonicalizer('file_B','file_B.canonic','#',1,5,1,1,1,1,10, ['\s*:\s*',' : ', '^','<', '$','>']);

creates two identical files 'file_A.canonic' and 'file_B.canonic':

   <birth date : 1961/8/4>
   <first name : barack>
   <last name : obama>
   <profession : president>


Mart E. Rivilis,


Please report any bugs or feature requests to, or through the web interface at I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.


You can find documentation for this module with the perldoc command.

   perldoc File::Canonicalizer

You can also look for information at:


Copyright 2013 Mart E. Rivilis.

This program is free software; you can redistribute it and/or modify it under the terms of the the Artistic License (2.0).