Gem Version CI Coverage Status Code Climate


guard-rubocop allows you to automatically check Ruby code style with RuboCop when files are modified.

Tested on MRI 2.5 - 3.0.


Please make sure to have Guard installed before continue.

Add guard-rubocop to your Gemfile:

“by group :development do gem ‘guard-rubocop’ end

and then execute:

“ $ bundle install

or install it yourself as:

“ $ gem install guard-rubocop

Add the default Guard::RuboCop definition to your Guardfile by running:

“ $ guard init rubocop


Please read the Guard usage documentation.


You can pass some options in Guardfile like the following example:

“by guard :rubocop, all_on_start: false, cli: [format, clang, rails] do # … end

Available Options

“by all_on_start: true # Check all files at Guard startup. # default: true cli: ‘–rails’ # Pass arbitrary RuboCop CLI arguments. # An array or string is acceptable. # default: nil cmd: ‘./bin/rubocop’ # Pass custom cmd to run rubocop. # default: rubocop

hide_stdout: false # Do not display console output (in case outputting to file). # default: false keep_failed: true # Keep failed files until they pass. # default: true notification: :failed # Display Growl notification after each run. # true - Always notify # false - Never notify # :failed - Notify only when failed # default: :failed launchy: nil # Filename to launch using Launchy after RuboCop runs. # default: nil

Using Launchy to view results

guard-rubocop can be configured to launch a results file in lieu of or in addition to outputing results to the terminal. Configure your Guardfile with the launchy option:

“uby guard :rubocop, cli: %w(–format fuubar –format html -o ./tmp/rubocop_results.html), launchy: ‘./tmp/rubocop_results.html’ do # … end

Advanced Tips

If you’re using a testing Guard plugin such as guard-rspec together with guard-rubocop in the TDD way (the red-green-refactor cycle), you might be uncomfortable with the offense reports from RuboCop in the red-green phase:

  • In the red-green phase, you’re not necessarily required to write clean code – you just focus writing code to pass the test. It means, in this phase, guard-rspec should be run but guard-rubocop should not.
  • In the refactor phase, you’re required to make the code clean while keeping the test passing. In this phase, both guard-rspec and guard-rubocop should be run.

In this case, you may consider making use of the group method in your Guardfile:


This group allows to skip running RuboCop when RSpec failed.

group :red_green_refactor, halt_on_fail: true do guard :rspec do # … end

guard :rubocop do # … end end

Note: You need to use guard-rspec 4.2.3 or later due to a bug where it unintentionally fails when there are no spec files to be run.


  1. Fork it
  2. Create your feature branch (git checkout -b my-new-feature)
  3. Commit your changes (git commit -am 'Add some feature')
  4. Push to the branch (git push origin my-new-feature)
  5. Create new Pull Request


Copyright (c) 2013–2020 Yuji Nakayama

See the LICENSE.txt for details.