Use bundler/inline instead

require "bundler/inline"

gemfile(true) do
  source "https://rubygems.org"
  gem "rack"
end

p defined?(Rack) # => "constant"

Grill

http://en.wikipedia.org/wiki/Grill_(jewelry)

Implant Gemfile into your script.

Installation

$ gem install grill

If you want to uninstall gems installed by Grill, delete $HOME/.grill directory.

Usage

#!ruby

require "grill"

p defined?(Rack) # => nil

Grill.implant <<-GEMFILE
  source :rubygems
  gem "rack"
GEMFILE

p defined?(Rack) # => "constant"

Or, more handy way to use as below (since v0.2.1):

$ cat $HOME/.grill/commontools
source :rubygems
gem "typhoeus"
gem "nokogiri"
gem "slop"

$ cat scraper.rb
require "grill"

Grill.implant :commontools

opts = Slop.parse do
  # ...
end

You can multiple implant as below (since v0.3.0):

# these args will be combined one file.
# so if first arg define "source" and second is not, 
# second arg's `gem` is affected by that

Grill.implant <<-FOO, <<-BAR, :commontools
  source :rubygems
  gem "typhoeus"
  gem "nokogiri"
FOO
  gem "rack"
BAR

# You got typhoeus, nokogiri, rack, and :commontools

Compatibility of Gemfile

It is completely compatible (you installed version) Bundler's Gemfile so you can use full spec of it for version fixation, :require, :path, etc.

When use this?

Grill is useful for your disposable scripts. Do you want to do that create directory and put Gemfile into it and bundle install; bundle exec foo.rb for disposable scripts?