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), 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 $PATH
.
--keep-file-descriptors
If you use the --binstubs
flag in bundle install(1), 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 spec/my_spec.rb
.
bundle exec
makes a number of changes to the shell environment,
then executes the command you specify in full.
bundle
from inside a command invoked by bundle exec
(using
$BUNDLE_BIN_PATH
)rails
, rspec
,
rackup
) for your bundle on $PATH
Gemfile
(by setting BUNDLE_GEMFILE
)-rbundler/setup
to $RUBYOPT
, which makes sure that
Ruby programs invoked in the subshell can see the gems in
the bundleIt also modifies Rubygems:
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 notGem.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 environmentGem.bin_path
to use the gems in the bundle,
making system executables workFinally, 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.
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`
end
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`
end
end
Bundler provides convenience helpers that wrap system
and exec
, and they
can be used like this:
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
).