Provided by: ruby-bundler_1.16.1-3_all bug


       bundle-exec - Execute a command in the context of the bundle


       bundle exec [--keep-file-descriptors] command


       This  command  executes the command, making all gems specified in the Gemfile(5) available
       to require in Ruby programs.

       Essentially, if you would normally have run something like rspec spec/my_spec.rb, and  you
       want   to   use   the   gems  specified  in  the  Gemfile(5)  and  installed  via  [bundle
       install(1)][bundle-install], you should run bundle exec rspec spec/my_spec.rb.

       Note that bundle exec does not require that an executable is  available  on  your  shell´s


              Exec  in Ruby 2.0 began discarding non-standard file descriptors. When this flag is
              passed, exec will revert to the 1.9 behaviour of passing all  file  descriptors  to
              the new process.


       If  you  use  the  --binstubs  flag  in  [bundle install(1)][bundle-install], Bundler will
       automatically create a directory (which defaults to app_root/bin) containing  all  of  the
       executables available from gems in the bundle.

       After  using  --binstubs,  bin/rspec  spec/my_spec.rb  is  identical  to bundle exec rspec


       bundle exec makes a number of changes to the shell environment, then executes the  command
       you specify in full.

       ·   make  sure  that  it´s  still  possible  to  shell out to bundle from inside a command
           invoked by bundle exec (using $BUNDLE_BIN_PATH)

       ·   put the directory containing executables (like rails, rspec, rackup) for  your  bundle
           on $PATH

       ·   make  sure  that  if  bundler is invoked in the subshell, it uses the same Gemfile (by
           setting BUNDLE_GEMFILE)

       ·   add -rbundler/setup to $RUBYOPT, which makes sure that Ruby programs  invoked  in  the
           subshell can see the gems in the bundle

       It also modifies Rubygems:

       ·   disallow loading additional gems not in the bundle

       ·   modify  the  gem  method  to  be  a no-op if a gem matching the requirements is in the
           bundle, and to raise a Gem::LoadError if it´s not

       ·   Define Gem.refresh to be a no-op, since the source index is always frozen  when  using
           bundler, and to prevent gems from the system leaking into the environment

       ·   Override Gem.bin_path to use the gems in the bundle, making system executables work

       ·   Add all gems in the bundle into Gem.loaded_specs

       Finally, bundle exec also implicitly modifies Gemfile.lock if the lockfile and the Gemfile
       do not match. Bundler needs the Gemfile to  determine  things  such  as  a  gem´s  groups,
       autorequire,  and  platforms, etc., and that information isn´t stored in the lockfile. The
       Gemfile and lockfile must be synced in order to bundle exec successfully, so  bundle  exec
       updates the lockfile beforehand.

       By  default,  when  attempting  to bundle exec to a file with a ruby shebang, Bundler will
       Kernel.load that file instead of using Kernel.exec. For the vast majority of  cases,  this
       is  a  performance  improvement.  In  a  rare  few  cases,  this  could  cause some subtle
       side-effects (such as dependence on  the  exact  contents  of  $0  or  __FILE__)  and  the
       optimization can be disabled by enabling the disable_exec_load setting.

   Shelling out
       Any  Ruby  code that opens a subshell (like system, backticks, or %x{}) will automatically
       use the current Bundler environment. If you need to shell out to a Ruby  command  that  is
       not part of your current bundle, use the with_clean_env method with a block. Any subshells
       created inside the block  will  be  given  the  environment  present  before  Bundler  was
       activated. For example, Homebrew commands run Ruby, but don´t work inside a bundle:

           Bundler.with_clean_env do
             `brew install wget`

       Using  with_clean_env is also necessary if you are shelling out to a different bundle. Any
       Bundler commands run in a subshell will inherit the current Gemfile, so commands that need
       to run in the context of a different bundle also need to use with_clean_env.

           Bundler.with_clean_env do
             Dir.chdir "/other/bundler/project" do
               `bundle exec ./script`

       Bundler  provides convenience helpers that wrap system and exec, and they can be used like

           Bundler.clean_system(´brew install wget´)
           Bundler.clean_exec(´brew install wget´)


       At present, the Rubygems plugin system requires all files named rubygems_plugin.rb on  the
       load  path  of  any  installed  gem when any Ruby code requires rubygems.rb. This includes
       executables installed into the system, like rails, rackup, and rspec.

       Since Rubygems plugins can contain arbitrary Ruby code, they commonly  end  up  activating
       themselves or their dependencies.

       For  instance,  the  gemcutter  0.5  gem depended on json_pure. If you had that version of
       gemcutter installed (even if you also had a newer version without this problem),  Rubygems
       would activate gemcutter 0.5 and json_pure <latest>.

       If your Gemfile(5) also contained json_pure (or a gem with a dependency on json_pure), the
       latest version on your system might conflict with the version in your Gemfile(5),  or  the
       snapshot version in your Gemfile.lock.

       If this happens, bundler will say:

           You have already activated json_pure 1.4.6 but your Gemfile
           requires json_pure 1.4.3. Consider using bundle exec.

       In  this  situation,  you  almost  certainly  want  to  remove the underlying gem with the
       problematic gem plugin. In general, the authors  of  these  plugins  (in  this  case,  the
       gemcutter gem) have released newer versions that are more careful in their plugins.

       You can find a list of all the gems containing gem plugins by running

           ruby -rubygems -e "puts Gem.find_files(´rubygems_plugin.rb´)"

       At  the  very  least, you should remove all but the newest version of each gem plugin, and
       also remove all gem plugins that you aren´t using (gem uninstall gem_name).

                                            July 2018                              BUNDLE-EXEC(1)