Using gist to achieve self contained bundled gems within a single ruby script

gist-bundler.rb

require 'tmpdir'
require 'fileutils'

# scope bundling for this script to a directory based on its path
tmpdir = "#{Dir.tmpdir}/script_bundler/#{File.expand_path(__FILE__).gsub(/\W+/, '_')}"
FileUtils.mkdir_p(tmpdir)

gemfile = "#{tmpdir}/Gemfile"
gemfile_lock = "#{gemfile}.lock"

FileUtils.rm_f(gemfile_lock) if ENV["FORCE_BUNDLE_INSTALL"]

needs_bundle_install ||= ! File.exist?(gemfile_lock)
needs_bundle_install ||= File.read(gemfile) != gemfile_contents

if needs_bundle_install
  File.open(gemfile, "w") do |f|
    f.write(gemfile_contents)
  end
end

ENV['BUNDLE_GEMFILE'] = gemfile
begin
  require "bundler"
rescue LoadError
  puts "Installing bundler..."
  system "gem install --quiet bundler"
  exec $0, *ARGV
end

if needs_bundle_install
  puts "Bundle installing gems..."
  Bundler::Installer.install(Bundler.root, Bundler.definition, :system => true)
end

Bundler.setup(:default)
Bundler.require(:default)

your-script.rb

#!/usr/bin/env ruby

# Add your gems here
#
gemfile_contents = <<-EOF
  source "http://rubygems.org"
  gem "some-gem"
EOF

require 'open-uri'
eval open('https://raw.github.com/gist/1770601/gist-bundler.rb').read, binding

# Your code goes here
#