Find

The Find module supports the top-down traversal of a set of file paths.

For example, to total the size of all files under your home directory, ignoring anything in a "dot" directory (e.g. $HOME/.ssh):

  require 'find'

  total_size = 0

  Find.find(ENV["HOME"]) do |path|
    if FileTest.directory?(path)
      if File.basename(path)[0] == ?.
        Find.prune       # Don't look any further into this directory.
      else
        next
      end
    else
      total_size += FileTest.size(path)
    end
  end