delete empty directories

gistfile1.txt

# list directories
dirs = `du -h`.split("\n")

# get empty ones
empty_dirs = dirs.select{|d| d.split("\t").first.strip == "0B" }

# get only names
dir_names = empty_dirs.map{|d| d.split("\t")[1] }

# delete them
dir_names.each {|dir| `rmdir "#{dir}"` }