Script to left pad numeric filenames with leading 0's

leftpad_numeric_filenames_with_zeros.rb

require 'pathname'

DIRECTORIES_TO_IGNORE = ['.git']
EXTENSIONS_TO_IGNORE = [ # not implemented
  /^.git*$/,
  '.DS_Store'
].freeze
MINIMUM_WIDTH = 3
MOVE_COMMAND = ->(current_path, destination_path) {
  # Change `git mv` to `mv`/`move` on (Linux/OS-X/*BSD)/Windows for use outside of a git repository
  system "git mv #{current_path} #{destination_path}"
}
PATH = '.'
RECURSE_DIRECTORY_PREDICATE = false

def leftpad_numeric_filenames_with_zeros(path, recursive = false)
  path.children.each do |child_path|
    if child_path.directory?
      leftpad_numeric_filenames_with_zeros(child_path, recursive) if
        recursive &&
        !(DIRECTORIES_TO_IGNORE.map { |dir| child_path.relative_path_from(PATH) != dir }.reduce { |a, b| a && b })
    else
      begin
        filename_without_extension = child_path.basename.to_s.sub(/\..*/, '')
        if Integer(filename_without_extension)
          original_path = child_path.cleanpath
          destination_path = "#{child_path.dirname}/#{filename_without_extension.rjust(MINIMUM_WIDTH, '0')}#{child_path.extname}"
          puts "Moving #{original_path} to #{destination_path}."
          MOVE_COMMAND.call(original_path, destination_path)
        end
      rescue => e
        # puts e
        # puts "#{child_path} not touched."
      end
    end
  end
end

path = Pathname.new(PATH)
leftpad_numeric_filenames_with_zeros(path, RECURSE_DIRECTORY_PREDICATE)