diff --git a/pkgs/ruby/.gitignore b/pkgs/ruby/.gitignore
new file mode 100644
index 0000000..c1a6109
--- /dev/null
+++ b/pkgs/ruby/.gitignore
@@ -0,0 +1,43 @@
+*.gem
+*.rbc
+
+/.byebug_history
+/.config/
+/.rake_tasks~
+/InstalledFiles/
+/pkg/
+/tmp/
+
+# Used by dotenv library to load environment variables.
+/.env
+
+# RSpec configuration and generated files.
+/.rspec
+/coverage/
+/spec/examples.txt
+/spec/reports/
+/test/tmp/
+/test/version_tmp/
+
+# Documentation cache and generated files.
+/.yardoc/
+/_yardoc/
+/doc/
+/rdoc/
+
+# Environment normalization.
+/.bundle/
+/vendor/bundle/
+/lib/bundler/man/
+
+# For a library or gem, you might want to ignore these files since the code is
+# intended to run in multiple environments; otherwise, check them in.
+/Gemfile.lock
+/.ruby-version
+/.ruby-gemset
+
+# Unless supporting rvm < 1.11.0 or doing something fancy, ignore this.
+/.rvmrc
+
+# Used by RuboCop. Remote config files pulled in from inherit_from directive.
+/.rubocop-https?--*
diff --git a/pkgs/ruby/.rubocop.yml b/pkgs/ruby/.rubocop.yml
new file mode 100644
index 0000000..45600f8
--- /dev/null
+++ b/pkgs/ruby/.rubocop.yml
@@ -0,0 +1,66 @@
+require:
+  - rubocop-performance
+  - rubocop-rake
+  - rubocop-rspec
+
+AllCops:
+  TargetRubyVersion: 3.0
+  DisplayCopNames: true
+  NewCops: enable
+
+Layout/AccessModifierIndentation:
+  EnforcedStyle: outdent
+
+Layout/LineLength:
+  Max: 80
+
+Lint/AmbiguousOperatorPrecedence:
+  Enabled: false
+
+Lint/ReturnInVoidContext:
+  Enabled: false
+
+Metrics/BlockLength:
+  Exclude:
+    - '*.gemspec'
+    - 'Rakefile'
+    - 'spec/**/*_spec.rb'
+
+RSpec/ContextWording:
+  Prefixes:
+    - 'and'
+    - 'for'
+    - 'when'
+    - 'with'
+    - 'without'
+
+RSpec/FilePath:
+  CustomTransform:
+    KernAux: kernaux
+
+RSpec/ExampleLength:
+  CountAsOne: ['array', 'hash', 'heredoc']
+
+Style/AndOr:
+  EnforcedStyle: conditionals
+
+Style/DoubleNegation:
+  Enabled: false
+
+Style/HashAsLastArrayItem:
+  Enabled: false
+
+Style/PerlBackrefs:
+  Enabled: false
+
+Style/TrailingCommaInArguments:
+  EnforcedStyleForMultiline: comma
+
+Style/TrailingCommaInArrayLiteral:
+  EnforcedStyleForMultiline: comma
+
+Style/TrailingCommaInHashLiteral:
+  EnforcedStyleForMultiline: comma
+
+Style/VariableInterpolation:
+  Enabled: false
diff --git a/pkgs/ruby/.simplecov b/pkgs/ruby/.simplecov
new file mode 100644
index 0000000..8c6bdb8
--- /dev/null
+++ b/pkgs/ruby/.simplecov
@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+if ENV['SKIP_COVERAGE'].to_s.empty?
+  SimpleCov.start do
+    minimum_coverage 95
+
+    add_filter '/spec/'
+  end
+end
diff --git a/pkgs/ruby/.yardopts b/pkgs/ruby/.yardopts
new file mode 100644
index 0000000..505c853
--- /dev/null
+++ b/pkgs/ruby/.yardopts
@@ -0,0 +1,4 @@
+--markup markdown
+--readme README.md
+--protected
+--private
diff --git a/pkgs/ruby/Gemfile b/pkgs/ruby/Gemfile
new file mode 100644
index 0000000..b455047
--- /dev/null
+++ b/pkgs/ruby/Gemfile
@@ -0,0 +1,8 @@
+# frozen_string_literal: true
+
+source 'https://rubygems.org'
+
+# Specify your gem's dependencies in kernaux.gemspec
+gemspec
+
+gem 'simplecov', require: false
diff --git a/pkgs/ruby/README.md b/pkgs/ruby/README.md
new file mode 100644
index 0000000..cd34507
--- /dev/null
+++ b/pkgs/ruby/README.md
@@ -0,0 +1,4 @@
+KernAux
+=======
+
+Auxiliary library for kernel development.
diff --git a/pkgs/ruby/Rakefile b/pkgs/ruby/Rakefile
new file mode 100644
index 0000000..bacb118
--- /dev/null
+++ b/pkgs/ruby/Rakefile
@@ -0,0 +1,46 @@
+# frozen_string_literal: true
+
+require 'bundler/gem_tasks'
+
+CLEAN << '.yardoc'
+CLEAN << 'coverage'
+CLEAN << 'doc'
+CLEAN << 'spec/examples.txt'
+
+desc 'Run default checks'
+task default: %i[test lint]
+
+desc 'Run tests'
+task test: :spec
+
+desc 'Run code analysis tools'
+task lint: :rubocop
+
+desc 'Fix code style (rubocop --auto-correct)'
+task fix: 'rubocop:auto_correct'
+
+begin
+  require 'rspec/core/rake_task'
+  RSpec::Core::RakeTask.new
+rescue LoadError
+  nil
+end
+
+begin
+  require 'rubocop/rake_task'
+  RuboCop::RakeTask.new
+rescue LoadError
+  nil
+end
+
+begin
+  require 'yard'
+  YARD::Rake::YardocTask.new
+rescue LoadError
+  nil
+end
+
+desc 'Open development console'
+task :console do
+  sh 'bundle', 'exec', File.expand_path(File.join('bin', 'console'), __dir__)
+end
diff --git a/pkgs/ruby/bin/console b/pkgs/ruby/bin/console
new file mode 100755
index 0000000..bde46c0
--- /dev/null
+++ b/pkgs/ruby/bin/console
@@ -0,0 +1,8 @@
+#!/usr/bin/env ruby
+# frozen_string_literal: true
+
+require 'bundler/setup'
+require 'kernaux'
+require 'pry'
+
+Pry.start
diff --git a/pkgs/ruby/bin/setup b/pkgs/ruby/bin/setup
new file mode 100755
index 0000000..5cc837a
--- /dev/null
+++ b/pkgs/ruby/bin/setup
@@ -0,0 +1,9 @@
+#!/usr/bin/env bash
+
+set -euo pipefail
+IFS=$'\n\t'
+set -vx
+
+bundle install
+
+# Do any other automated setup that you need to do here
diff --git a/pkgs/ruby/kernaux.gemspec b/pkgs/ruby/kernaux.gemspec
new file mode 100644
index 0000000..a9e184a
--- /dev/null
+++ b/pkgs/ruby/kernaux.gemspec
@@ -0,0 +1,50 @@
+# frozen_string_literal: true
+
+require_relative 'lib/kernaux/version'
+
+Gem::Specification.new do |spec|
+  repo = 'https://github.com/tailix/libkernaux'
+
+  spec.name     = 'kernaux'
+  spec.version  = KernAux::VERSION
+  spec.license  = 'MIT'
+  spec.homepage = "#{repo}/tree/master/pkgs/ruby"
+  spec.platform = Gem::Platform::RUBY
+  spec.summary  = 'Auxiliary library for kernel development'
+
+  spec.required_ruby_version = '~> 3.0'
+
+  spec.authors = ['Alex Kotov']
+  spec.email   = %w[kotovalexarian@gmail.com]
+
+  spec.description = <<~DESCRIPTION.split("\n").map(&:strip).join ' '
+    Auxiliary library for kernel development.
+  DESCRIPTION
+
+  spec.metadata['homepage_uri']          = spec.homepage
+  spec.metadata['source_code_uri']       = spec.homepage
+  spec.metadata['bug_tracker_uri']       = "#{repo}/issues"
+  spec.metadata['rubygems_mfa_required'] = 'true'
+
+  spec.bindir        = 'exe'
+  spec.require_paths = ['lib']
+
+  spec.files = Dir.chdir File.expand_path __dir__ do
+    `git ls-files -z`.split("\x0").reject do |f|
+      f.match %r{\A(?:test|spec|features)/}
+    end
+  end
+
+  spec.executables = spec.files.grep(%r{\Aexe/}) { |f| File.basename f }
+
+  spec.add_development_dependency 'bundler', '~> 2.2'
+  spec.add_development_dependency 'pry',     '~> 0.14'
+  spec.add_development_dependency 'rake',    '~> 13.0'
+  spec.add_development_dependency 'rspec',               '~> 3.10'
+  spec.add_development_dependency 'rubocop',             '~> 1.25'
+  spec.add_development_dependency 'rubocop-performance', '~> 1.13'
+  spec.add_development_dependency 'rubocop-rake',        '~> 0.6'
+  spec.add_development_dependency 'rubocop-rspec',       '~> 2.7'
+  spec.add_development_dependency 'simplecov',           '~> 0.21'
+  spec.add_development_dependency 'yard',                '~> 0.9'
+end
diff --git a/pkgs/ruby/lib/kernaux.rb b/pkgs/ruby/lib/kernaux.rb
new file mode 100644
index 0000000..05f48de
--- /dev/null
+++ b/pkgs/ruby/lib/kernaux.rb
@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+require_relative 'kernaux/version'
+
+##
+# Auxiliary library for kernel development.
+#
+module KernAux
+end
diff --git a/pkgs/ruby/lib/kernaux/version.rb b/pkgs/ruby/lib/kernaux/version.rb
new file mode 100644
index 0000000..2fa888f
--- /dev/null
+++ b/pkgs/ruby/lib/kernaux/version.rb
@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+module KernAux
+  # Gem version.
+  VERSION = '0.0.0'
+end
diff --git a/pkgs/ruby/spec/lib/kernaux_spec.rb b/pkgs/ruby/spec/lib/kernaux_spec.rb
new file mode 100644
index 0000000..932373a
--- /dev/null
+++ b/pkgs/ruby/spec/lib/kernaux_spec.rb
@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe KernAux do
+  describe '::VERSION' do
+    specify do
+      expect(described_class::VERSION).to match(/\A\d+\.\d+\.\d+\z/)
+    end
+  end
+end
diff --git a/pkgs/ruby/spec/spec_helper.rb b/pkgs/ruby/spec/spec_helper.rb
new file mode 100644
index 0000000..eb964ec
--- /dev/null
+++ b/pkgs/ruby/spec/spec_helper.rb
@@ -0,0 +1,104 @@
+# frozen_string_literal: true
+
+# This should be on the top of the file.
+require 'simplecov'
+
+# This file was generated by the `rspec --init` command. Conventionally, all
+# specs live under a `spec` directory, which RSpec adds to the `$LOAD_PATH`.
+# The generated `.rspec` file contains `--require spec_helper` which will cause
+# this file to always be loaded, without a need to explicitly require it in any
+# files.
+#
+# Given that it is always loaded, you are encouraged to keep this file as
+# light-weight as possible. Requiring heavyweight dependencies from this file
+# will add to the boot time of your test suite on EVERY test run, even for an
+# individual file that may not need all of that loaded. Instead, consider making
+# a separate helper file that requires the additional dependencies and performs
+# the additional setup, and require it from the spec files that actually need
+# it.
+#
+# See http://rubydoc.info/gems/rspec-core/RSpec/Core/Configuration
+
+require 'kernaux'
+
+RSpec.configure do |config|
+  # rspec-expectations config goes here. You can use an alternate
+  # assertion/expectation library such as wrong or the stdlib/minitest
+  # assertions if you prefer.
+  config.expect_with :rspec do |expectations|
+    # This option will default to `true` in RSpec 4. It makes the `description`
+    # and `failure_message` of custom matchers include text for helper methods
+    # defined using `chain`, e.g.:
+    #     be_bigger_than(2).and_smaller_than(4).description
+    #     # => "be bigger than 2 and smaller than 4"
+    # ...rather than:
+    #     # => "be bigger than 2"
+    expectations.include_chain_clauses_in_custom_matcher_descriptions = true
+  end
+
+  # rspec-mocks config goes here. You can use an alternate test double
+  # library (such as bogus or mocha) by changing the `mock_with` option here.
+  config.mock_with :rspec do |mocks|
+    # Prevents you from mocking or stubbing a method that does not exist on
+    # a real object. This is generally recommended, and will default to
+    # `true` in RSpec 4.
+    mocks.verify_partial_doubles = true
+  end
+
+  # This option will default to `:apply_to_host_groups` in RSpec 4 (and will
+  # have no way to turn it off -- the option exists only for backwards
+  # compatibility in RSpec 3). It causes shared context metadata to be
+  # inherited by the metadata hash of host groups and examples, rather than
+  # triggering implicit auto-inclusion in groups with matching metadata.
+  config.shared_context_metadata_behavior = :apply_to_host_groups
+
+  # This allows you to limit a spec run to individual examples or groups
+  # you care about by tagging them with `:focus` metadata. When nothing
+  # is tagged with `:focus`, all examples get run. RSpec also provides
+  # aliases for `it`, `describe`, and `context` that include `:focus`
+  # metadata: `fit`, `fdescribe` and `fcontext`, respectively.
+  config.filter_run_when_matching :focus
+
+  # Allows RSpec to persist some state between runs in order to support
+  # the `--only-failures` and `--next-failure` CLI options. We recommend
+  # you configure your source control system to ignore this file.
+  config.example_status_persistence_file_path = 'spec/examples.txt'
+
+  # Limits the available syntax to the non-monkey patched syntax that is
+  # recommended. For more details, see:
+  #   - http://rspec.info/blog/2012/06/rspecs-new-expectation-syntax/
+  #   - http://www.teaisaweso.me/blog/2013/05/27/rspecs-new-message-expectation-syntax/
+  #   - http://rspec.info/blog/2014/05/notable-changes-in-rspec-3/#zero-monkey-patching-mode
+  config.disable_monkey_patching!
+
+  # This setting enables warnings. It's recommended, but in some cases may
+  # be too noisy due to issues in dependencies.
+  config.warnings = true
+
+  # Many RSpec users commonly either run the entire suite or an individual
+  # file, and it's useful to allow more verbose output when running an
+  # individual spec file.
+  if config.files_to_run.one?
+    # Use the documentation formatter for detailed output,
+    # unless a formatter has already been configured
+    # (e.g. via a command-line flag).
+    config.default_formatter = 'doc'
+  end
+
+  # Print the 10 slowest examples and example groups at the
+  # end of the spec run, to help surface which specs are running
+  # particularly slow.
+  config.profile_examples = 10
+
+  # Run specs in random order to surface order dependencies. If you find an
+  # order dependency and want to debug it, you can fix the order by providing
+  # the seed, which is printed after each run.
+  #     --seed 1234
+  config.order = :random
+
+  # Seed global randomization in this process using the `--seed` CLI option.
+  # Setting this allows you to use `--seed` to deterministically reproduce
+  # test failures related to randomization by passing the same `--seed` value
+  # as the one that triggered the failure.
+  Kernel.srand config.seed
+end