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Configurable tool for analyzing Slim templates


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slim-lint is a tool to help keep your Slim files clean and readable. In addition to style and lint checks, it integrates with RuboCop to bring its powerful static analysis tools to your Slim templates.

You can run slim-lint manually from the command line, or integrate it into your SCM hooks.


  • Ruby 3.0+ (for Ruby 2.x support, use slim-lint 0.24.0 or older)
  • Slim 3.0+


gem install slim_lint


Run slim-lint from the command line by passing in a directory (or multiple directories) to recursively scan:

slim-lint app/views/

You can also specify a list of files explicitly:

slim-lint app/**/*.slim

slim-lint will output any problems with your Slim, including the offending filename and line number.

Command Line Flag Description
-c/--config Specify which configuration file to use
-e/--exclude Exclude one or more files from being linted
-i/--include-linter Specify which linters you specifically want to run
-x/--exclude-linter Specify which linters you don't want to run
--stdin-file-path [file] Pipe source from STDIN, using file in offense reports
--[no-]color Whether to output in color
--reporter [reporter] Specify which output formatter to use
--show-linters Show all registered linters
--show-reporters Show all available reporters
-h/--help Show command line flag documentation
-v/--version Show version
-V/--verbose-version Show detailed version information


slim-lint will automatically recognize and load any file with the name .slim-lint.yml as a configuration file. It loads the configuration based on the directory slim-lint is being run from, ascending until a configuration file is found. Any configuration loaded is automatically merged with the default configuration (see config/default.yml).

Here's an example configuration file:

  - 'exclude/files/in/this/directory/from/all/linters/**/*.slim'

      - 'app/views/directory_of_files_to_exclude/**/*.slim'
      - 'specific/file/to/exclude.slim'

    include: 'specific/directory/to/include/**/*.slim'
    max: 100

    enabled: false

All linters have an enabled option which can be true or false, which controls whether the linter is run, along with linter-specific options. The defaults are defined in config/default.yml.

Linter Options

Option Description
enabled If false, this linter will never be run. This takes precedence over any other option.
include List of files or glob patterns to scope this linter to. This narrows down any files specified via the command line.
exclude List of files or glob patterns to exclude from this linter. This excludes any files specified via the command line or already filtered via the include option.

Global File Exclusion

The exclude global configuration option allows you to specify a list of files or glob patterns to exclude from all linters. This is useful for ignoring third-party code that you don't maintain or care to lint. You can specify a single string or a list of strings for this option.

Skipping Frontmatter

Some static blog generators such as Jekyll include leading frontmatter to the template for their own tracking purposes. slim-lint allows you to ignore these headers by specifying the skip_frontmatter option in your .slim-lint.yml configuration:

skip_frontmatter: true

Disabling Linters For Specific Code

Slim-lint linters

To disable a slim-lint linter, you can use a slim comment:

/ slim-lint:disable TagCase
IMG src="images/cat.gif"
/ slim-lint:enable TagCase

Rubocop cops

To disable Rubocop cop, you can use a comment control statement:

- # rubocop:disable Rails/OutputSafety
p = raw(@blog.content)
- # rubocop:enable Rails/OutputSafety


You can find detailed documentation on all supported linters by following the link below:

Editor Integration

Sublime Text

Install the Sublime slim-lint plugin.


If you use Flycheck, support for slim-lint is included as of version 20160718.215 installed from MELPA.


Install the linter-slim-lint plugin by running apm install linter-slim-lint.

Visual Studio Code

Install the VS Code slim-lint plugin.

Git Integration

If you'd like to integrate slim-lint into your Git workflow, check out overcommit, a powerful and flexible Git hook manager.

Rake Integration

To execute slim-lint via a Rake task, make sure you have rake included in your gem path (e.g. via Gemfile), and add the following to your Rakefile:

require 'slim_lint/rake_task'

By default, when you execute rake slim_lint, the above configuration is equivalent to running slim-lint ., which will lint all .slim files in the current directory and its descendants.

You can customize your task by writing:

require 'slim_lint/rake_task' do |t|
  t.config = 'custom/config.yml'
  t.files = ['app/views', 'custom/*.slim']
  t.quiet = true # Don't display output from slim-lint to STDOUT

You can also use this custom configuration with a set of files specified via the command line:

# Single quotes prevent shell glob expansion
rake 'slim_lint[app/views, custom/*.slim]'

Files specified in this manner take precedence over the task's files attribute.


We love getting feedback with or without pull requests. If you do add a new feature, please add tests so that we can avoid breaking it in the future.

Speaking of tests, we use rspec, which can be run by executing the following from the root directory of the repository:

bundle exec rspec


If you're interested in seeing the changes and bug fixes between each version of slim-lint, read the Slim-Lint Changelog.


This project is released under the MIT license.