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

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.