Ruby: how do I recursively find and remove empty directories?

Question

I'm trying to write some ruby that would recursively search a given directory for all empty child directories and remove them.

Thoughts?

Note: I'd like a script version if possible. This is both a practical need and a something to help me learn.

Answer 1

Why not just use shell?

find . -type d -empty -exec rmdir '{}' \;

Does exactly what you want.

Answer 2

In ruby:

Dir['**/*']                                            \
  .select { |d| File.directory? d }                    \
  .select { |d| (Dir.entries(d) - %w[ . .. ]).empty? } \
  .each   { |d| Dir.rmdir d }

Answer 3

Dir.glob('**/*').each do |dir|
  begin
    Dir.rmdir dir if File.directory?(dir)
  # rescue # this can be dangereous unless used cautiously
  rescue Errno::ENOTEMPTY
  end
end

Answer 4

I've tested this script on OS X, but if you are on Windows, you'll need to make changes.

You can find the files in a directory, including hidden files, with Dir#entries.

This code will delete directories which become empty once you've deleted any sub-directories.

def entries(dir)
  Dir.entries(dir) - [".", ".."]
end

def recursively_delete_empty(dir)
  subdirs = entries(dir).map { |f| File.join(dir, f) }.select { |f| File.directory? f }
  subdirs.each do |subdir|
    recursively_delete_empty subdir
  end

  if entries(dir).empty?
    puts "deleting #{dir}"
    Dir.rmdir dir
  end
end

Answer 5

module MyExtensions
  module FileUtils
    # Gracefully delete dirs that are empty (or contain empty children).
    def rmdir_empty(*dirs)
      dirs.each do |dir|
        begin
          ndel = Dir.glob("#{dir}/**/", File::FNM_DOTMATCH).count do |d|
            begin; Dir.rmdir d; rescue SystemCallError; end
          end
        end while ndel > 0
      end
    end
  end

  module ::FileUtils
    extend FileUtils
  end
end