BUNDLE-INSTALL(1)					     BUNDLE-INSTALL(1)



NAME
       bundle-install - Install the dependencies specified in your Gemfile

SYNOPSIS
       bundle install [--local] [--quiet] [--gemfile=GEMFILE] [--system]



			[--deployment] [--frozen] [--path]
			[--binstubs[=DIRECTORY]] [--without=GROUP1[ GROUP2...]]



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 speci-
       fied 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 gen-
	      eral, bundler will assume that the location of the Gemfile(5) is
	      also  the  project  root, and will look for the Gemfile.lock and
	      vendor/cache relative to it.

       --path=<path>
	      The location to install the gems in the bundle to. This defaults
	      to the gem home, which is the location that gem install installs
	      gems to. This means that, by default, gems installed  without  a
	      --path  setting  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 located in vendor/cache. Note that if a more appropri-
	      ate platform-specific gem  exists  on  rubygems.org,  this  will
	      bypass the normal lookup.

       --deployment
	      Switches bundler's defaults into deployment mode.

       --binstubs[=<directory>]
	      Create  a  directory  (defaults to bin) containing an executable
	      that runs in the context of the bundle.  For  instance,  if  the
	      rails gem comes with a rails executable, this flag will create a
	      bin/rails executable that ensures  that  all  dependencies  used
	      come from the bundled gems.

DEPLOYMENT MODE
       Bundler's defaults are optimized for development. To switch to defaults
       optimized for deployment, use the --deployment flag.

       1.  A Gemfile.lock is required.

	   To ensure that the same versions of the gems you developed with and
	   tested  with  are  also  used  in  deployments,  a  Gemfile.lock is
	   required.

	   This is mainly to ensure that  you  remember  to  check  your  Gem-
	   file.lock into version control.

       2.  The Gemfile.lock must be up to date

	   In  development,  you  can modify your Gemfile(5) and re-run bundle
	   install to conservatively update your Gemfile.lock snapshot.

	   In deployment, your Gemfile.lock should be up-to-date with  changes
	   made in your Gemfile(5).

       3.  Gems  are  installed to vendor/bundle not your default system loca-
	   tion

	   In 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  permis-
	   sion to read them.

	   As  a result, bundle install --deployment installs gems to the ven-
	   dor/bundle directory in the application.  This  may	be  overridden
	   using the --path option.



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:

       o   Updating your Gemfile.lock

       o   Updating your vendor/cache, if necessary

       o   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.

       As a result, you should run bundle install as  the  current  user,  and
       bundler will ask for your password if it is needed to perform the final
       step.

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 speci-
       fied 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 environ-
       ments.

       For a simple illustration, consider the following Gemfile(5):



	   source "http://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 (surpris-
       ingly) 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.lock is out of date.

       --path Subsequent calls to bundle install  will	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
	      --without  in  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 appli-
       cation 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 "http://rubygems.org"

	   gem "actionpack", "2.3.8"
	   gem "activemerchant"



       In this case, both actionpack and activemerchant depend	on  activesup-
       port.  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 "http://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	depen-
       dency 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 satify another dependency

       Because you did not explicitly ask to update activemerchant, you  would
       not  expect it to suddenly stop working after updating actionpack. How-
       ever, satisfying the new activesupport 3.0.0.rc dependency  of  action-
       pack requires updating one of its dependencies.

       Even  though activemerchant declares a very loose dependency that theo-
       retically 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) bundle-update.1.html.



				 October 2010		     BUNDLE-INSTALL(1)
