 
      bundle install
                bundle-install - Install the dependencies specified in your Gemfile
              
bundle install [--gemfile=GEMFILE]
                 [--path PATH] [--system]
                 [--without=GROUP1[ GROUP2...]]
                 [--local] [--deployment]
                 [--binstubs[=DIRECTORY]]
                 [--standalone[=GROUP1[ GROUP2...]]]
                 [--trust-policy=POLICY]
                 [--jobs=SIZE]
                 [--retry=TRIES]
                 [--no-cache]
                 [--quiet]
                 [--clean]
                 [--full-index]
                 [--no-prune]
                 [--shebang]Description
Install the gems specified in your Gemfile(5). If this is the first
              time you run bundle install (and a Gemfile.lock does not exist),
              bundler will fetch all remote sources, resolve dependencies and
              install all needed gems.
If a Gemfile.lock does exist, and you have not updated your Gemfile(5),
              bundler will fetch all remote sources, but use the dependencies
              specified in the Gemfile.lock instead of resolving dependencies.
If a Gemfile.lock does exist, and you have updated your Gemfile(5),
              bundler will use the dependencies in the Gemfile.lock for all gems
              that you did not update, but will re-resolve the dependencies of
              gems that you did update. You can find more information about this
              update process below under CONSERVATIVE UPDATING.
Options
- --gemfile=<gemfile>
- The location of the Gemfile(5) that bundler should use. This defaults to a gemfile in the current working directory. In general, bundler will assume that the location of the Gemfile(5) is also the project root, and will look for the - Gemfile.lockand- vendor/cacherelative to it.
- --path=<path>
- The location to install the gems in the bundle to. This defaults to Rubygems' gem home, which is also the default location where - gem installinstalls gems. This means that, by default, gems installed without a- --pathsetting will show up in- gem list. This setting is a remembered option.
- --system
- Installs the gems in the bundle to the system location. This overrides any previous remembered use of - --path.
- --without=<list>
- A space-separated list of groups to skip installing. This is a remembered option. 
- --local
- Do not attempt to connect to - rubygems.org, instead using just the gems already present in Rubygems' cache or in- vendor/cache. Note that if a more appropriate platform-specific gem exists on- rubygems.org, it will not be found.
- --deployment
- Switches bundler's defaults into deployment mode. Do not use this flag on development machines. 
- --binstubs[=<directory>]
- Create a directory (defaults to - bin) containing an executable that runs in the context of the bundle. For instance, if the- railsgem comes with a- railsexecutable, this flag will create a- bin/railsexecutable that ensures that all dependencies used come from the bundled gems.
- --shebang ruby-install-name
- Uses the ruby executable (usually - ruby) provided to execute the scripts created with --binstubs. For instance, if you use --binstubs with- --shebang jruby, all executables will be created to use jruby instead.
- --standalone[=<list>]
- Make a bundle that can work without Ruby Gems or Bundler at runtime. It takes a space separated list of groups to install. It creates a - bundledirectory and installs the bundle there. It also generates a- bundle/bundler/setup.rbfile to replace Bundler's own setup.
- --trust-policy=[<policy>]
- Apply the Rubygems security policy named policy, where policy is one of HighSecurity, MediumSecurity, LowSecurity, AlmostNoSecurity, or NoSecurity. For more detail, see the Rubygems signing documentation, linked below in SEE ALSO. 
- --jobs=[<size>]
- Install gems parallely by starting size number of parallel workers. 
- --retry[<tries]
- Retries failed network or git requests tries times. 
- --no-cache
- Do not update the cache in - vendor/cachewith the newly bundled gems. This does not remove any existing cached gems, only stops the newly bundled gems from being cached during the install.
- --quiet
- Do not print progress information to stdout. Instead, communicate the success of the install operation via exit status code. 
- --clean
- Run bundle clean automatically after install. 
- --full-index
- Use the rubygems modern index instead of the API endpoint. 
- --no-prune
- Don't remove stale gems from the cache. 
Deployment Mode
Bundler's defaults are optimized for development. To switch to
              defaults optimized for deployment, use the --deployment flag.
              Do not activate deployment mode on development machines, as it
              will cause in an error when the Gemfile is modified.
- 
              A Gemfile.lockis required.To ensure that the same versions of the gems you developed with and tested with are also used in deployments, a Gemfile.lockis required.This is mainly to ensure that you remember to check your Gemfile.lockinto version control.
- 
              The Gemfile.lockmust be up to dateIn development, you can modify your Gemfile(5) and re-run bundle installto conservatively update yourGemfile.locksnapshot.In deployment, your Gemfile.lockshould be up-to-date with changes made in your Gemfile(5).
- 
              Gems are installed to vendor/bundlenot your default system locationIn development, it's convenient to share the gems used in your application with other applications and other scripts run on the system. In deployment, isolation is a more important default. In addition, the user deploying the application may not have permission to install gems to the system, or the web server may not have permission to read them. As a result, bundle install --deploymentinstalls gems to thevendor/bundledirectory in the application. This may be overridden using the--pathoption.
Sudo Usage
By default, bundler installs gems to the same location as gem install.
In some cases, that location may not be writable by your Unix user. In
              that case, bundler will stage everything in a temporary directory,
              then ask you for your sudo password in order to copy the gems into
              their system location.
From your perspective, this is identical to installing them gems directly into the system.
You should never use sudo bundle install. This is because several
              other steps in bundle install must be performed as the current user:
- Updating your Gemfile.lock
- Updating your vendor/cache, if necessary
- Checking out private git repositories using your user's SSH keys
Of these three, the first two could theoretically be performed by
              chowning the resulting files to $SUDO_USER. The third, however,
              can only be performed by actually invoking the git command as
              the current user. Therefore, git gems are downloaded and installed
              into ~/.bundle rather than $GEM_HOME or $BUNDLE_PATH.
As a result, you should run bundle install as the current user,
              and bundler will ask for your password if it is needed to put the
              gems into their final location.
Installing Groups
By default, bundle install will install all gems in all groups
              in your Gemfile(5), except those declared for a different platform.
However, you can explicitly tell bundler to skip installing
              certain groups with the --without option. This option takes
              a space-separated list of groups.
While the --without option will skip installing the gems in the
              specified groups, it will still download those gems and use them to
              resolve the dependencies of every gem in your Gemfile(5).
This is so that installing a different set of groups on another machine (such as a production server) will not change the gems and versions that you have already developed and tested against.
Bundler offers a rock-solid guarantee that the third-party
code you are running in development and testing is also the
third-party code you are running in production. You can choose
to exclude some of that code in different environments, but you
will never be caught flat-footed by different versions of
third-party code being used in different environments.
For a simple illustration, consider the following Gemfile(5):
source "https://rubygems.org"
gem "sinatra"
group :production do
  gem "rack-perftools-profiler"
end
In this case, sinatra depends on any version of Rack (>= 1.0, while
              rack-perftools-profiler depends on 1.x (~> 1.0).
When you run bundle install --without production in development, we
              look at the dependencies of rack-perftools-profiler as well. That way,
              you do not spend all your time developing against Rack 2.0, using new
              APIs unavailable in Rack 1.x, only to have bundler switch to Rack 1.2
              when the production group is used.
This should not cause any problems in practice, because we do not
              attempt to install the gems in the excluded groups, and only evaluate
              as part of the dependency resolution process.
This also means that you cannot include different versions of the same gem in different groups, because doing so would result in different sets of dependencies used in development and production. Because of the vagaries of the dependency resolution process, this usually affects more than just the gems you list in your Gemfile(5), and can (surprisingly) radically change the gems you are using.
Remembered Options
Some options (marked above in the OPTIONS section) are remembered
              between calls to bundle install, and by the Bundler runtime.
For instance, if you run bundle install --without test, a subsequent
              call to bundle install that does not include a --without flag will
              remember your previous choice.
In addition, a call to Bundler.setup will not attempt to make the
              gems in those groups available on the Ruby load path, as they were
              not installed.
The settings that are remembered are:
- --deployment
- At runtime, this remembered setting will also result in Bundler raising an exception if the - Gemfile.lockis out of date.
- --path
- Subsequent calls to - bundle installwill install gems to the directory originally passed to- --path. The Bundler runtime will look for gems in that location. You can revert this option by running- bundle install --system.
- --binstubs
- Bundler will update the executables every subsequent call to - bundle install.
- --without
- As described above, Bundler will skip the gems specified by - --withoutin subsequent calls to- bundle install. The Bundler runtime will also not try to make the gems in the skipped groups available.
The Gemfile.lock
When you run bundle install, Bundler will persist the full names
              and versions of all gems that you used (including dependencies of
              the gems specified in the Gemfile(5)) into a file called Gemfile.lock.
Bundler uses this file in all subsequent calls to bundle install,
              which guarantees that you always use the same exact code, even
              as your application moves across machines.
Because of the way dependency resolution works, even a seemingly small change (for instance, an update to a point-release of a dependency of a gem in your Gemfile(5)) can result in radically different gems being needed to satisfy all dependencies.
As a result, you SHOULD check your Gemfile.lock into version
              control. If you do not, every machine that checks out your
              repository (including your production server) will resolve all
              dependencies again, which will result in different versions of
              third-party code being used if any of the gems in the Gemfile(5)
              or any of their dependencies have been updated.
Conservative Updating
When you make a change to the Gemfile(5) and then run bundle install,
              Bundler will update only the gems that you modified.
In other words, if a gem that you did not modify worked before
              you called bundle install, it will continue to use the exact
              same versions of all dependencies as it used before the update.
Let's take a look at an example. Here's your original Gemfile(5):
source "https://rubygems.org"
gem "actionpack", "2.3.8"
gem "activemerchant"
In this case, both actionpack and activemerchant depend on
              activesupport. The actionpack gem depends on activesupport 2.3.8
              and rack ~> 1.1.0, while the activemerchant gem depends on
              activesupport >= 2.3.2, braintree >= 2.0.0, and builder >= 2.0.0.
When the dependencies are first resolved, Bundler will select
              activesupport 2.3.8, which satisfies the requirements of both
              gems in your Gemfile(5).
Next, you modify your Gemfile(5) to:
source "https://rubygems.org"
gem "actionpack", "3.0.0.rc"
gem "activemerchant"
The actionpack 3.0.0.rc gem has a number of new dependencies,
              and updates the activesupport dependency to = 3.0.0.rc and
              the rack dependency to ~> 1.2.1.
When you run bundle install, Bundler notices that you changed
              the actionpack gem, but not the activemerchant gem. It
              evaluates the gems currently being used to satisfy its requirements:
- activesupport 2.3.8
- also used to satisfy a dependency in activemerchant, which is not being updated
- rack ~> 1.1.0
- not currently being used to satisfy another dependency
Because you did not explicitly ask to update activemerchant,
              you would not expect it to suddenly stop working after updating
              actionpack. However, satisfying the new activesupport 3.0.0.rc
              dependency of actionpack requires updating one of its dependencies.
Even though activemerchant declares a very loose dependency
              that theoretically matches activesupport 3.0.0.rc, bundler treats
              gems in your Gemfile(5) that have not changed as an atomic unit
              together with their dependencies. In this case, the activemerchant
              dependency is treated as activemerchant 1.7.1 + activesupport 2.3.8,
              so bundle install will report that it cannot update actionpack.
To explicitly update actionpack, including its dependencies
              which other gems in the Gemfile(5) still depend on, run
              bundle update actionpack (see bundle update(1)).
Summary: In general, after making a change to the Gemfile(5) , you
              should first try to run bundle install, which will guarantee that no
              other gems in the Gemfile(5) are impacted by the change. If that
              does not work, run bundle update(1).
See Also
- Gem install docs: http://guides.rubygems.org/rubygems-basics/#installing-gems
- Rubygems signing docs: http://guides.rubygems.org/security/