Provided by: bundler_1.3.5-2ubuntu1_all 
NAME
Gemfile - A format for describing gem dependencies for Ruby programs
SYNOPSIS
A Gemfile describes the gem dependencies required to execute associated Ruby code.
Place the Gemfile in the root of the directory containing the associated code. For
instance, in a Rails application, place the Gemfile in the same directory as the Rakefile.
SYNTAX
A Gemfile is evaluated as Ruby code, in a context which makes available a number of
methods used to describe the gem requirements.
SOURCES (#source)
At the top of the Gemfile, add one line for each Rubygems source that might contain the
gems listed in the Gemfile.
source "https://rubygems.org"
source "http://gems.github.com"
Each of these _source_s MUST be a valid Rubygems repository. Sources are checked for gems
following the heuristics described in SOURCE PRIORITY.
RUBY (#ruby)
If your application requires a specific Ruby version or engine, specify your requirements
using the ruby method, with the following arguments. All parameters are OPTIONAL unless
otherwise specified.
VERSION (required)
The version of Ruby that your application requires. If your application requires an
alternate Ruby engine, such as JRuby or Rubinius, this should be the Ruby version that the
engine is compatible with.
ruby "1.9.3"
ENGINE (:engine)
Each application may specify a Ruby engine. If an engine is specified, an engine version
must also be specified.
ENGINE VERSION (:engine_version)
Each application may specify a Ruby engine version. If an engine version is specified, an
engine must also be specified. If the engine is "ruby" the engine version specified must
match the Ruby version.
ruby "1.8.7", :engine => "jruby", :engine_version => "1.6.7"
GEMS (#gem)
Specify gem requirements using the gem method, with the following arguments. All
parameters are OPTIONAL unless otherwise specified.
NAME (required)
For each gem requirement, list a single gem line.
gem "nokogiri"
VERSION
Each gem MAY have one or more version specifiers.
gem "nokogiri", ">= 1.4.2"
gem "RedCloth", ">= 4.1.0", "< 4.2.0"
REQUIRE AS (:require)
Each gem MAY specify files that should be used when autorequiring via Bundler.require. You
may pass an array with multiple files, or false to prevent any file from being
autorequired.
gem "redis", :require => ["redis/connection/hiredis", "redis"]
gem "webmock", :require => false
The argument defaults to the name of the gem. For example, these are identical:
gem "nokogiri"
gem "nokogiri", :require => "nokogiri"
GROUPS (:group or :groups)
Each gem MAY specify membership in one or more groups. Any gem that does not specify
membership in any group is placed in the default group.
gem "rspec", :group => :test
gem "wirble", :groups => [:development, :test]
The Bundler runtime allows its two main methods, Bundler.setup and Bundler.require, to
limit their impact to particular groups.
# setup adds gems to Ruby´s load path
Bundler.setup # defaults to all groups
require "bundler/setup" # same as Bundler.setup
Bundler.setup(:default) # only set up the _default_ group
Bundler.setup(:test) # only set up the _test_ group (but `not` _default_)
Bundler.setup(:default, :test) # set up the _default_ and _test_ groups, but no others
# require requires all of the gems in the specified groups
Bundler.require # defaults to just the _default_ group
Bundler.require(:default) # identical
Bundler.require(:default, :test) # requires the _default_ and _test_ groups
Bundler.require(:test) # requires just the _test_ group
The Bundler CLI allows you to specify a list of groups whose gems bundle install should
not install with the --without option. To specify multiple groups to ignore, specify a
list of groups separated by spaces.
bundle install --without test
bundle install --without development test
After running bundle install --without test, bundler will remember that you excluded the
test group in the last installation. The next time you run bundle install, without any
--without option, bundler will recall it.
Also, calling Bundler.setup with no parameters, or calling require "bundler/setup" will
setup all groups except for the ones you excluded via --without (since they are obviously
not available).
Note that on bundle install, bundler downloads and evaluates all gems, in order to create
a single canonical list of all of the required gems and their dependencies. This means
that you cannot list different versions of the same gems in different groups. For more
details, see Understanding Bundler http://gembundler.com/rationale.html.
PLATFORMS (:platforms)
If a gem should only be used in a particular platform or set of platforms, you can specify
them. Platforms are essentially identical to groups, except that you do not need to use
the --without install-time flag to exclude groups of gems for other platforms.
There are a number of Gemfile platforms:
ruby C Ruby (MRI) or Rubinius, but NOT Windows
ruby_18
ruby AND version 1.8
ruby_19
ruby AND version 1.9
ruby_20
ruby AND version 2.0
mri Same as ruby, but not Rubinius
mri_18 mri AND version 1.8
mri_19 mri AND version 1.9
mri_20 mri AND version 2.0
rbx Same as ruby, but only Rubinius (not MRI)
jruby JRuby
mswin Windows
mingw Windows ´mingw32´ platform (aka RubyInstaller)
mingw_18
mingw AND version 1.8
mingw_19
mingw AND version 1.9
mingw_20
mingw AND version 2.0
As with groups, you can specify one or more platforms:
gem "weakling", :platforms => :jruby
gem "ruby-debug", :platforms => :mri_18
gem "nokogiri", :platforms => [:mri_18, :jruby]
All operations involving groups (bundle install, Bundler.setup, Bundler.require) behave
exactly the same as if any groups not matching the current platform were explicitly
excluded.
GIT (:git)
If necessary, you can specify that a gem is located at a particular git repository. The
repository can be public (http://github.com/rails/rails.git) or private
(git@github.com:rails/rails.git). If the repository is private, the user that you use to
run bundle install MUST have the appropriate keys available in their $HOME/.ssh.
Git repositories are specified using the :git parameter. The group, platforms, and require
options are available and behave exactly the same as they would for a normal gem.
gem "rails", :git => "git://github.com/rails/rails.git"
A git repository SHOULD have at least one file, at the root of the directory containing
the gem, with the extension .gemspec. This file MUST contain a valid gem specification, as
expected by the gem build command. It MUST NOT have any dependencies, other than on the
files in the git repository itself and any built-in functionality of Ruby or Rubygems.
If a git repository does not have a .gemspec, bundler will attempt to create one, but it
will not contain any dependencies, executables, or C extension compilation instructions.
As a result, it may fail to properly integrate into your application.
If a git repository does have a .gemspec for the gem you attached it to, a version
specifier, if provided, means that the git repository is only valid if the .gemspec
specifies a version matching the version specifier. If not, bundler will print a warning.
gem "rails", "2.3.8", :git => "git://github.com/rails/rails.git"
# bundle install will fail, because the .gemspec in the rails
# repository´s master branch specifies version 3.0.0
If a git repository does not have a .gemspec for the gem you attached it to, a version
specifier MUST be provided. Bundler will use this version in the simple .gemspec it
creates.
Git repositories support a number of additional options.
branch, tag, and ref
You MUST only specify at most one of these options. The default is :branch =>
"master"
submodules
Specify :submodules => true to cause bundler to expand any submodules included in
the git repository
If a git repository contains multiple .gemspecs, each .gemspec represents a gem located at
the same place in the file system as the .gemspec.
|~rails [git root]
| |-rails.gemspec [rails gem located here]
|~actionpack
| |-actionpack.gemspec [actionpack gem located here]
|~activesupport
| |-activesupport.gemspec [activesupport gem located here]
|...
To install a gem located in a git repository, bundler changes to the directory containing
the gemspec, runs gem build name.gemspec and then installs the resulting gem. The gem
build command, which comes standard with Rubygems, evaluates the .gemspec in the context
of the directory in which it is located.
GITHUB (:github)
If the git repository you want to use is hosted on GitHub and is public, you can use the
:github shorthand to specify just the github username and repository name (without the
trailing ".git"), separated by a slash. If both the username and repository name are the
same, you can omit one.
gem "rails", :github => "rails/rails"
gem "rails", :github => "rails"
Are both equivalent to
gem "rails", :git => "git://github.com/rails/rails.git"
PATH (:path)
You can specify that a gem is located in a particular location on the file system.
Relative paths are resolved relative to the directory containing the Gemfile.
Similar to the semantics of the :git option, the :path option requires that the directory
in question either contains a .gemspec for the gem, or that you specify an explicit
version that bundler should use.
Unlike :git, bundler does not compile C extensions for gems specified as paths.
gem "rails", :path => "vendor/rails"
BLOCK FORM OF GIT, PATH, GROUP and PLATFORMS
The :git, :path, :group, and :platforms options may be applied to a group of gems by using
block form.
git "git://github.com/rails/rails.git" do
gem "activesupport"
gem "actionpack"
end
platforms :ruby do
gem "ruby-debug"
gem "sqlite3"
end
group :development do
gem "wirble"
gem "faker"
end
In the case of the git block form, the :ref, :branch, :tag, and :submodules options may be
passed to the git method, and all gems in the block will inherit those options.
GEMSPEC (#gemspec)
If you wish to use Bundler to help install dependencies for a gem while it is being
developed, use the gemspec method to pull in the dependencies listed in the .gemspec file.
The gemspec method adds any runtime dependencies as gem requirements in the default group.
It also adds development dependencies as gem requirements in the development group.
Finally, it adds a gem requirement on your project (:path => ´.´). In conjunction with
Bundler.setup, this allows you to require project files in your test code as you would if
the project were installed as a gem; you need not manipulate the load path manually or
require project files via relative paths.
The gemspec method supports optional :path, :name, and :development_group options, which
control where bundler looks for the .gemspec, what named .gemspec it uses (if more than
one is present), and which group development dependencies are included in.
SOURCE PRIORITY
When attempting to locate a gem to satisfy a gem requirement, bundler uses the following
priority order:
1. The source explicitly attached to the gem (using :path or :git)
2. For implicit gems (dependencies of explicit gems), any git or path repository
otherwise declared. This results in bundler prioritizing the ActiveSupport gem from
the Rails git repository over ones from rubygems.org
3. The sources specified via source, searching each source in your Gemfile from last
added to first added.
April 2013 GEMFILE(5)