One-liner to recursively list directories in Ruby?

Dir.glob("**/*/") # for directories
Dir.glob("**/*") # for all files

Instead of Dir.glob(foo) you can also write Dir[foo] (however Dir.glob can also take a block, in which case it will yield each path instead of creating an array).

Ruby Glob Docs

I believe none of the solutions here deal with hidden directories (e.g. '.test'):

require 'find'
Find.find('.') { |e| puts e if File.directory?(e) }

For list of directories try

Dir['**/']

List of files is harder, because in Unix directory is also a file, so you need to test for type or remove entries from returned list which is parent of other entries.

Dir['**/*'].reject {|fn| File.directory?(fn) }

And for list of all files and directories simply

Dir['**/*']

Fast one liner

Only directories

`find -type d`.split("\n")

Directories and normal files

`find -type d -or -type f`.split("\n")`

Pure beautiful ruby

require "pathname"

def rec_path(path, file= false)
  puts path
  path.children.collect do |child|
    if file and child.file?
      child
    elsif child.directory?
      rec_path(child, file) + [child]
    end
  end.select { |x| x }.flatten(1)
end

# only directories
rec_path(Pathname.new(dir), false)
# directories and normal files
rec_path(Pathname.new(dir), true)

As noted in other answers here, you can use Dir.glob. Keep in mind that folders can have lots of strange characters in them, and glob arguments are patterns, so some characters have special meanings. As such, it's unsafe to do something like the following:

Dir.glob("#{folder}/**/*")

Instead do:

Dir.chdir(folder) { Dir.glob("**/*").map {|path| File.expand_path(path) } }