Ruby script to find top-level empty directories in a working SVN directory tree (forked and fixed because original script was not properly working for more complicated directory structure)

find-empty-dir-in-svn.rb

##
# Ruby script to find top-level empty directories in a working SVN directory tree
#
# A directory is considered empty, if there are zero files reachable through this directory (excluding
# files under .svn directories). That means that a directory containing other empty directories is
# also empty (recursively). The algorithm will consolidate the output so that it only contains
# top-level empty directories, but not their sub-directories.
#
# The output of this script can be used, for example to remove non-used parts of a SVN repository:
#   ruby empty_dirs.rb | xargs svn del
##

require 'find'

dir_to_scan = '.'
dir_to_scan = ARGV[0] if ARGV.count == 1

dirs = []

# First collect all directories, but ignore anything with .svn in it
Find.find( dir_to_scan ) do |entry|
    next if entry =~ /\.svn/
    next if not File.directory?(entry)
    dirs << entry
end

dirs_count = {}

# Fetch the dirs and count number of entries(dirs, files), excluding .svn again
dirs.each do |dir|
    dirs_count[dir] =
        Dir.entries(dir).collect { |e|
            case e
            when '.svn'
                nil
            when '.'
                nil
            when '..'
                nil
            else
                e
            end
        }.compact.count
end

# Traverse the directory tree and adjust the number of entries for each directory
dirs_count_copy = dirs_count.dup
dirs_count_copy.each do |dir,count|
    if count == 0
        depth = dir.count('/');
        while depth > 1
            depth = depth - 1
            dir = dir[0..(dir.length-dir.split('/').last.length-2)]
            dirs_count[dir] = dirs_count[dir] - 1;
            if (dirs_count[dir] > 0)
                break
            end
        end
    end
end

# Filter the hashmap to only contain all empty directories
empty_dirs = {}
dirs_count.each do |dir,count|
    if count == 0
        empty_dirs[dir] = 1;
    end
end

# Consolidate the list to only top-level empty directories
empty_dirs.each do |parent,c|
    empty_dirs.each do |possible_child,c|
        if possible_child.index(parent+'/')
            empty_dirs.delete(possible_child)
        end
    end
end

# Output empty top-level directories one-by-one
empty_dirs.each do |dir,c|
    puts dir.gsub(' ', '\\ ')
end

Nice, thanks! I only suggest adding shebang at the top, so you could run it as a script on linux and mac.

#!/usr/bin/env ruby