Guard is a command line tool to easily handle events on file system modifications.
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Guard is a command line tool to easily handle events on file system modifications.

This document contains a lot of information, please take your time and read these instructions carefully. If you have any questions, ask them in our Google group or on #guard (

Before you file an issue, make sure you have read the file an issue section that contains some important information.


  • FSEvent support on Mac OS X.
  • Inotify support on Linux.
  • Directory Change Notification support on Windows.
  • Polling on the other operating systems.
  • Automatic and super fast file modification detection when polling is not used. Even new and deleted files are detected.
  • Support for visual system notifications.
  • Tested against Ruby 1.8.7, 1.9.2, 1.9.3, REE and the latest versions of JRuby & Rubinius.


Ryan Bates made an excellent RailsCast about Guard and you should definitely watch it for a nice introduction to Guard.


The simplest way to install Guard is to use Bundler.

Add Guard to your Gemfile:

group :development do
  gem 'guard'

and install it by running Bundler:

$ bundle

Generate an empty Guardfile with:

$ guard init

If you are using Windows and want colors in your terminal, you'll have to add the win32console gem to your Gemfile and install it with Bundler:

group :development do
  gem 'win32console'

It's important that you always run Guard through Bundler to avoid errors. If you're getting sick of typing bundle exec all the time, try the Rubygems Bundler.

System notifications

You can configure Guard to make use of the following system notification libraries, but it's strongly recommended to use either Ruby GNTP, Libnotify or Notifu:


  • Runs on Mac OS X
  • Supports all Growl versions

The growl gem is compatible with all versions of Growl and uses a command line tool growlnotify that must be separately downloaded and installed. The version of the command line tool must match your Growl version. The growl gem does not support multiple notification channels.

You have to download the installer for growlnotify from the Growl download section.

To use growl you have to add it to your Gemfile and run bundler:

group :development do
  gem 'growl'


There's currently a bug in Growl that prevents displaying the icons through GNTP, see issue #231. Use the growl gem until fixed.

The ruby_gntp gem sends system notifications over the network with the Growl Notification Transport Protocol and supports local and remote notifications.

Guard supports multiple notification channels for customizing each notification type. For Growl on Mac OS X you need to have at least version 1.3 installed.

To use ruby_gntp you have to add it to your Gemfile and run bundler:

group :development do
  gem 'ruby_gntp'


  • Runs on Linux, FreeBSD, OpenBSD and Solaris
  • Supports Libnotify

The libnotify gem supports the Gnome libnotify notification daemon, but it can be used on other window managers as well. You have to install the libnotify-bin package with your favorite package manager.

To use libnotify you have to add it to your Gemfile and run bundler:

group :development do
  gem 'libnotify'

If you are unable to build the libnotify gem on your system, Guard also has a built in notifier - notifysend - that shells out to the notify-send utility that comes with libnotify-bin.


  • Runs on Windows
  • Supports Notifu

The rb-notifu gem supports Windows system tray notifications.

To use rb-notifu you have to add it to your Gemfile and run bundler:

group :development do
  gem 'rb-notifu'


  • Runs on Mac OS X
  • Supports Growl version >= 1.3
  • Doesn't support JRuby and MacRuby.
  • Doesn't work when forking, e.g. with Spork.

The growl_notify gem uses AppleScript to send Growl notifications. The gem needs a native C extension to make use of AppleScript and does not run on JRuby and MacRuby.

Guard supports multiple notification channels for customizing each notification type and you need to have at least Growl version 1.3 installed.

To use growl_notify you have to add it to your Gemfile and run bundler:

group :development do
  gem 'growl_notify'

Add more Guards

Guard is now ready to use and you should add some Guards for your specific use. Start exploring the many Guards available by browsing the Guard organization on GitHub or by searching for guard- on RubyGems.

When you have found a Guard of your interest, add it to your Gemfile:

group :development do
  gem '<guard-name>'

See the init section of the Guard usage below to see how to install the supplied Guard template that you can install and to suit your needs.


Guard is run from the command line. Please open your terminal and go to your project work directory.


You can always get help on the available tasks with the help task:

$ guard help

To request more detailed help on a specific task is simple: just appending the task name to the help task. For example, to get help for the start task, simply run:

$ guard help start


You can generate a Guardfile and have all installed guards be automatically added into it by running the init task without any option:

$ guard init

You can also specify the name of an installed Guard to only get that Guard in the generated Guardfile:

$ guard init <guard-name>

You can also define your own templates in ~/.guard/templates/ which can be appended in the same way to your existing Guardfile:

$ guard init <template-name>

Note: If you already have a Guardfile in the current directory, the init task can be used to append a supplied Guard template from an installed Guard to your existing Guardfile.

-b/--bare option

You can generate an empty Guardfile by running the init task with the bare option:

$ guard init --bare
$ guard init -b # shortcut


Just launch Guard inside your Ruby or Rails project with:

$ guard

Guard will look for a Guardfile in your current directory. If it does not find one, it will look in your $HOME directory for a .Guardfile.

-c/--clear option

The shell can be cleared after each change:

$ guard --clear
$ guard -c # shortcut

-n/--notify option

System notifications can be disabled:

$ guard --notify false
$ guard -n f # shortcut

Notifications can also be disabled globally by setting a GUARD_NOTIFY environment variable to false.

-g/--group option

Only certain Guard groups can be run:

$ guard --group group_name another_group_name
$ guard -g group_name another_group_name # shortcut

See the Guardfile DSL below for creating groups.

-v/--verbose option

Guard can be run in verbose mode:

$ guard --verbose
$ guard -v # shortcut

-w/--watchdir option

Guard can watch in any directory instead of the current directory:

$ guard --watchdir ~/your/fancy/project
$ guard -w ~/your/fancy/project # shortcut

-G/--guardfile option

Guard can use a Guardfile not located in the current directory:

$ guard --guardfile ~/.your_global_guardfile
$ guard -G ~/.your_global_guardfile # shortcut

-A/--watch-all-modifications option

Guard can optionally watch all file modifications like moves or deletions with:

$ guard start -A
$ guard start --watch-all-modifications

-i/--no-interactions option

Turn off completely any Guard terminal interactions with:

$ guard start -i
$ guard start --no-interactions

-I/--no-vendor option

Ignore the use of vendored gems with:

$ guard start -I
$ guard start --no-vendor

-B/--no-bundler-warning option

Skip Bundler warning when a Gemfile exists in the project directory but Guard is not run with Bundler.

$ guard start -B
$ guard start --no-bundler-warning


You can list the available Guards with the list task:

$ guard list

Available guards:
   rspec *
See also
* denotes ones already in your Guardfile


You can show the structure of the groups and their Guards with the show task:

$ guard show

Group backend:
  rspec: cli => "--color --format doc"
Group frontend:
  coffeescript: output => "public/javascripts/compiled"

This shows the internal structure of the evaluated Guardfile or .Guardfile, with the .guard.rb file. You can read more about these files in the shared configuration section below.


You can interact with Guard and enter commands when Guard has nothing to do. Guard understands the following commands:

  • : Run all Guards.
  • h, help: Show a help of the available interactor commands.
  • r, reload: Reload all Guards.
  • n, notification: Toggle system notifications on and off.
  • p, pause: Toggles the file modification listener. The prompt will change to p> when paused. This is useful when switching Git branches, rebase Git or change whitespace.
  • e, exit: Stop all Guards and quit Guard.

Instead of running all Guards with the key, you can also run a single Guard by entering its name:

> rspec

It's also possible to run all Guards within a group by entering the group name:

> frontend

The same applies to Guard reloading. You can reload a Guard with the following command:

> ronn reload

This will reload only the Ronn Guard. You can also reload all Guards within a group:

> backend reload

Readline support

With Readline enabled, you'll see a command prompt > when Guard is ready to accept a command. The command line supports history navigation with the and arrow keys, and command auto-completion with the key.

Unfortunately Readline does not work on MRI on Mac OS X by default. You can work around the issue by installing a pure Ruby implementation:

platforms :ruby do
  gem 'rb-readline'

Guard will automatically enable Readline support if your environment supports it, but you can disable Readline with the interactor DSL method or turn off completely with the --no-interactions option.


You can also interact with Guard by sending POSIX signals to the Guard process (all but Windows).

Pause watching

$ kill -USR1 <guard_pid>

Continue watching

$ kill -USR2 <guard_pid>

Guardfile DSL

The Guardfile DSL is evaluated as plain Ruby, so you can use normal Ruby code in your Guardfile. Guard itself provides the following DSL methods that can be used for configuration:


The guard method allows you to add a Guard to your toolchain and configure it by passing the options after the name of the Guard:

guard :coffeescript, :input => 'coffeescripts', :output => 'javascripts'

You can define the same Guard more than once:

guard :coffeescript, :input => 'coffeescripts', :output => 'javascripts'
guard :coffeescript, :input => 'specs', :output => 'specs'


The watch method allows you to define which files are watched by a Guard:

guard :bundler do

String watch patterns are matched with String#==. You can also pass a regular expression to the watch method:

guard :jessie do

This instructs the jessie Guard to watch for file changes in the spec folder, but only for file names that ends with _spec or Spec and have a file type of js or coffee.

You can easily test your watcher regular expressions with Rubular.

When you add a block to the watch expression, you can modify the file name that has been detected before sending it to the Guard for processing:

guard :rspec do
  watch(%r{^lib/(.+)\.rb$})     { |m| "spec/lib/#{m[1]}_spec.rb" }

In this example the regular expression capture group (.+) is used to transform a file change in the lib folder to its test case in the spec folder. Regular expression watch patterns are matched with Regexp#match.

You can also launch any arbitrary command in the supplied block:

guard :shell do
  watch('.*') { `git status` }


The group method allows you to group several Guards together. This comes in handy especially when you have a huge Guardfile and want to focus your development on a certain part.

group :specs do
  guard :rspec do

group :docs do
  guard :ronn do

Groups to be run can be specified with the Guard DSL option --group (or -g):

$ guard -g specs

Guards that don't belong to a group are considered global and are always run.


If you don't specify any notification configuration in your Guardfile, Guard goes through the list of available notifiers and takes the first that is available. If you specify your preferred library, auto detection will not take place:

notification :growl

will select the growl gem for notifications. You can also set options for a notifier:

notification :growl, :sticky => true

Each notifier has a slightly different set of supported options:

notification :growl, :sticky => true, :host => '', :password => 'secret'
notification :gntp, :sticky => true, :host => '', :password => 'secret'
notification :growl_notify, :sticky => true, :priority => 0
notification :libnotify, :timeout => 5, :transient => true, :append => false, :urgency => :critical
notification :notifu, :time => 5, :nosound => true, :xp => true

It's possible to use more than one notifier. This allows you to configure different notifiers for different OS if your project is developed cross-platform or if you like to have local and remote notifications.

Notifications can also be turned off in the Guardfile, in addition to setting the environment variable GUARD_NOTIFY or using the cli switch -n:

notification :off


You can disable the interactor auto detection and for a specific implementation:

interactor :readline

will select Readline interactor. You can also force the simple interactor without Readline support with:

interactor :simple

If you do not need the keyboard interactions with Guard at all, you can turn them off:

interactor :off


The callback method allows you to execute arbitrary code before or after any of the start, stop, reload, run_all and run_on_change Guards' method. You can even insert more hooks inside these methods.

guard :rspec do

  callback(:start_begin) { `mate .` }

Please see the hooks and callbacks page in the Guard wiki for more details.


The ignore_paths method allows you to ignore top level directories altogether. This comes is handy when you have large amounts of non-source data in you project. By default .bundle, .git, log, tmp, and vendor are ignored. Currently it is only possible to ignore the immediate descendants of the watched directory.

ignore_paths 'public'


ignore_paths 'foo', 'bar'

notification :growl_notify
notification :gntp, :host => ''

group :backend do
  guard :bundler do

  guard :rspec, :cli => '--color --format doc' do
    watch(%r{^lib/(.+)\.rb$})         { |m| "spec/lib/#{m[1]}_spec.rb" }
    watch(%r{^spec/models/.+\.rb$})   { ["spec/models", "spec/acceptance"] }
    watch(%r{^spec/.+\.rb$})          { `say hello` }
    watch('spec/spec_helper.rb')      { "spec" }

group :frontend do
  guard :coffeescript, :output => 'public/javascripts/compiled' do

  guard :livereload do

Shared configurations

You may optionally place a .Guardfile in your home directory to use it across multiple projects. It's evaluated when you have no Guardfile in your current directory.

If a .guard.rb is found in your home directory, it will be appended to the Guardfile in your current directory. This can be used for tasks you want guard to handle but other users probably don't.

For example, indexing your source tree with Ctags:

guard :shell do
  watch(%r{^(?:app|lib)/.+\.rb$}) { `ctags -R` }

Advanced Linux system configuration

It's not uncommon to encounter a system limit on the number of files you can monitor. For example, Ubuntu Lucid's (64bit) inotify limit is set to 8192.

You can get your current inotify file watch limit by executing:

$ cat /proc/sys/fs/inotify/max_user_watches

And set a new limit temporary with:

sudo sysctl fs.inotify.max_user_watches=524288
sudo sysctl -p

If you like to make your limit permanent, use:

echo fs.inotify.max_user_watches=524288 | sudo tee -a /etc/sysctl.conf
sudo sysctl -p

You may also need to pay attention to the values of max_queued_events and max_user_instances.

Create a Guard

Creating a new Guard is very easy. For example, to create a Guard named yoyo just create a new gem by running bundle gem guard-yoyo. Please make your Guard start with guard-, so that it can easily be found on RubyGems.

$ mkdir guard-yoyo
$ cd guard-yoyo
$ bundle gem guard-yoyo

Now extend the project structure to have an initial Guard:

.travis.yml  # bonus point! # bonus point!
        Guardfile # needed for `guard init <guard-name>`
test/ # or spec/

Your Guard main class Guard::Yoyo in lib/guard/guard-yoyo.rb must inherit from Guard::Guard and should overwrite at least the #run_on_change task methods.

Here is an example scaffold for lib/guard/yoyo.rb:

require 'guard'
require 'guard/guard'

module Guard
  class Yoyo < Guard

    # Initialize a Guard.
    # @param [Array<Guard::Watcher>] watchers the Guard file watchers
    # @param [Hash] options the custom Guard options
    def initialize(watchers = [], options = {})

    # Call once when Guard starts. Please override initialize method to init stuff.
    # @raise [:task_has_failed] when start has failed
    def start

    # Called when `stop|quit|exit|s|q|e + enter` is pressed (when Guard quits).
    # @raise [:task_has_failed] when stop has failed
    def stop

    # Called when `reload|r|z + enter` is pressed.
    # This method should be mainly used for "reload" (really!) actions like reloading passenger/spork/bundler/...
    # @raise [:task_has_failed] when reload has failed
    def reload

    # Called when just `enter` is pressed
    # This method should be principally used for long action like running all specs/tests/...
    # @raise [:task_has_failed] when run_all has failed
    def run_all

    # Called on file(s) modifications that the Guard watches.
    # @param [Array<String>] paths the changes files or paths
    # @raise [:task_has_failed] when run_on_change has failed
    def run_on_change(paths)

    # Called on file(s) deletions that the Guard watches.
    # @param [Array<String>] paths the deleted files or paths
    # @raise [:task_has_failed] when run_on_change has failed
    def run_on_deletion(paths)


Please take a look at the source code of some of the existing Guards for more concrete example and inspiration.

Alternatively, a new Guard can be added inline to a Guardfile with this basic structure:

require 'guard/guard'

module ::Guard
  class InlineGuard < ::Guard::Guard
    def run_all

    def run_on_change(paths)

@avdi has a very cool inline Guard example in his blog post A Guardfile for Redis.

Programmatic use of Guard

The Guardfile DSL can also be used in a programmatic fashion by calling Guard::Dsl.evaluate_guardfile.

Available options are as follow:

  • :guardfile - The path to a valid Guardfile.
  • :guardfile_contents - A string representing the content of a valid Guardfile.

Remember, without any options given, Guard will look for a Guardfile in your current directory and if it does not find one, it will look for it in your $HOME directory.

Evaluate a Guardfile:

require 'guard'

Guard.start(:guardfile => '/path/to/Guardfile')

Evaluate a string as Guardfile:

require 'guard'


guardfile = <<-EOF
  guard 'rspec' do

Guard.start(:guardfile_contents => guardfile)

File an issue

You can report bugs and feature requests to GitHub Issues.

Please don't ask question in the issue tracker, instead ask them in our Google group or on #guard (

Try to figure out where the issue belongs to: Is it an issue with Guard itself or with a Guard implementation you're using?

When you file a bug, please try to follow these simple rules if applicable:

  • Make sure you run Guard with bundle exec first.
  • Add verbose information to the issue by running Guard with the --verbose option.
  • Add your Guardfile and Gemfile to the issue.
  • Make sure that the issue is reproducible with your description.

It's most likely that your bug gets resolved faster if you provide as much information as possible!

Development Dependency Status

Pull requests are very welcome! Please try to follow these simple rules if applicable:

  • Please create a topic branch for every separate change you make.
  • Make sure your patches are well tested. All specs run with rake spec:portability must pass.
    • On OS X you need to compile once rb-fsevent executable with rake build_mac_exec.
  • Update the Yard documentation.
  • Update the README.
  • Update the CHANGELOG for noteworthy changes.
  • Please do not change the version number.

For questions please join us in our Google group or on #guard (


Thibaud Guillaume-Gentil (@thibaudgg)

Core Team