search.rb

class Search

  def initialize(search_str, base_dir, search_depth)
    @search_str = search_str
    @base_dir = base_dir
    @search_depth = search_depth
  end

  def do_search
    search_dir(@base_dir, @search_depth)
  end

  private

  def add?(full_path)
    file_name = File.basename(full_path)
    file_name.include?(@search_str)
  end

  def search_dir(current_dir, depth)
    result = []
    return result if depth == 0

    Dir[current_dir + '/*'].each do |current_file|
      if File.directory?(current_file)
        children = search_dir(current_file, depth - 1)
        result.concat(children)
      else
        result.push(current_file) if add?(current_file)
      end
    end
    result
  end

end

search = Search.new('Directory', 'Filename', 5)
files = search.do_search
files.each {|file| puts file}