XKCD approved password generator (https://www.xkcd.com/936/)

clave.rb

# https://www.xkcd.com/936/
module Clave
  extend self

  def run
    puts((1..4).map { safe_words.sample }.join(" "))
  end

  private

  SAFE_SET = /\A[A-Za-z]+\Z/.freeze

  def safe_words
    @safe ||= words.select{ |w| SAFE_SET.match(w) }
  end

  def words
    @words ||= File.read("/usr/share/dict/spanish").split("\n")
  end
end

Clave.run if __FILE__ == $PROGRAM_NAME