http://blog.n-z.jp/blog/2014-06-25-env-array-hash.html

env_ltsv_each.rb

# -*- coding: utf-8 -*-
# env_ltsv_each.rb
# https://gist.github.com/znz/849166c048a2117c341d
# copyright (c) 2014 Kazuhiro NISHIYAMA
# This software is released under the MIT License.
# http://opensource.org/licenses/MIT
require 'ostruct'

def env_ltsv_each(prefix, start: 0, encoding: Encoding::UTF_8, scrub: false)
  block_given? or return enum_for(__method__)
  i = start
  loop do
    ltsv = ENV["#{prefix}_#{i}"]
    i = i.succ
    break unless ltsv
    h = OpenStruct.new
    ltsv.split("\t").each do |pair|
      key, value = pair.split(':', 2)
      value.force_encoding(encoding)
      value.scrub!(scrub) if scrub
      h[key] = value
    end
    yield h
  end
  nil
end

if __FILE__ == $0
  ENV['NAVI_0'] = 'icon:top	label:Top	uri:/'
  ENV['NAVI_1'] = 'icon:posts	label:Listing Posts	uri:/posts'
  ENV['NAVI_2'] = 'icon:users	label:Listing Users	uri:/users'
  env_ltsv_each('NAVI') do |h|
    puts %Q(<a href="#{h.uri}"><img src="#{h.icon}.png" alt="#{h.label}"></a>)
    #=>
    # <a href="/"><img src="top.png" alt="Top"></a>
    # <a href="/posts"><img src="posts.png" alt="Listing Posts"></a>
    # <a href="/users"><img src="users.png" alt="Listing Users"></a>
  end
end