diff --git a/.rubocop.yml b/.rubocop.yml
index 12e6553f..99e1e2b3 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -6,14 +6,6 @@ AllCops:
   Exclude:
   - lib/jekyll/collection.rb
   - lib/jekyll/command.rb
-  - lib/jekyll/commands/build.rb
-  - lib/jekyll/commands/clean.rb
-  - lib/jekyll/commands/doctor.rb
-  - lib/jekyll/commands/help.rb
-  - lib/jekyll/commands/new.rb
-  - lib/jekyll/commands/serve
-  - lib/jekyll/commands/serve/servlet.rb
-  - lib/jekyll/commands/serve.rb
   - lib/jekyll/configuration.rb
   - lib/jekyll/converter.rb
   - lib/jekyll/converters/identity.rb
diff --git a/lib/jekyll/commands/build.rb b/lib/jekyll/commands/build.rb
index baa4e88a..cef13c91 100644
--- a/lib/jekyll/commands/build.rb
+++ b/lib/jekyll/commands/build.rb
@@ -5,8 +5,8 @@ module Jekyll
         # Create the Mercenary command for the Jekyll CLI for this Command
         def init_with_program(prog)
           prog.command(:build) do |c|
-            c.syntax      'build [options]'
-            c.description 'Build your site'
+            c.syntax      "build [options]"
+            c.description "Build your site"
             c.alias :b
 
             add_build_options(c)
@@ -27,15 +27,17 @@ module Jekyll
           options = configuration_from_options(options)
           site = Jekyll::Site.new(options)
 
-          if options.fetch('skip_initial_build', false)
-            Jekyll.logger.warn "Build Warning:", "Skipping the initial build. This may result in an out-of-date site."
+          if options.fetch("skip_initial_build", false)
+            Jekyll.logger.warn "Build Warning:", "Skipping the initial build." \
+                        " This may result in an out-of-date site."
           else
             build(site, options)
           end
 
-          if options.fetch('detach', false)
-            Jekyll.logger.info "Auto-regeneration:", "disabled when running server detached."
-          elsif options.fetch('watch', false)
+          if options.fetch("detach", false)
+            Jekyll.logger.info "Auto-regeneration:",
+              "disabled when running server detached."
+          elsif options.fetch("watch", false)
             watch(site, options)
           else
             Jekyll.logger.info "Auto-regeneration:", "disabled. Use --watch to enable."
@@ -50,12 +52,13 @@ module Jekyll
         # Returns nothing.
         def build(site, options)
           t = Time.now
-          source      = options['source']
-          destination = options['destination']
-          incremental = options['incremental']
+          source      = options["source"]
+          destination = options["destination"]
+          incremental = options["incremental"]
           Jekyll.logger.info "Source:", source
           Jekyll.logger.info "Destination:", destination
-          Jekyll.logger.info "Incremental build:", (incremental ? "enabled" : "disabled. Enable with --incremental")
+          Jekyll.logger.info "Incremental build:",
+            (incremental ? "enabled" : "disabled. Enable with --incremental")
           Jekyll.logger.info "Generating..."
           process_site(site)
           Jekyll.logger.info "", "done in #{(Time.now - t).round(3)} seconds."
@@ -68,7 +71,7 @@ module Jekyll
         #
         # Returns nothing.
         def watch(_site, options)
-          External.require_with_graceful_fail 'jekyll-watch'
+          External.require_with_graceful_fail "jekyll-watch"
           Jekyll::Watcher.watch(options)
         end
       end # end of class << self
diff --git a/lib/jekyll/commands/clean.rb b/lib/jekyll/commands/clean.rb
index ca19d9b5..3a44d596 100644
--- a/lib/jekyll/commands/clean.rb
+++ b/lib/jekyll/commands/clean.rb
@@ -4,8 +4,9 @@ module Jekyll
       class << self
         def init_with_program(prog)
           prog.command(:clean) do |c|
-            c.syntax 'clean [subcommand]'
-            c.description 'Clean the site (removes site output and metadata file) without building.'
+            c.syntax "clean [subcommand]"
+            c.description "Clean the site " \
+                  "(removes site output and metadata file) without building."
 
             add_build_options(c)
 
@@ -17,13 +18,13 @@ module Jekyll
 
         def process(options)
           options = configuration_from_options(options)
-          destination = options['destination']
-          metadata_file = File.join(options['source'], '.jekyll-metadata')
-          sass_cache = File.join(options['source'], '.sass-cache')
+          destination = options["destination"]
+          metadata_file = File.join(options["source"], ".jekyll-metadata")
+          sass_cache = File.join(options["source"], ".sass-cache")
 
-          remove(destination, checker_func: :directory?)
-          remove(metadata_file, checker_func: :file?)
-          remove(sass_cache, checker_func: :directory?)
+          remove(destination, :checker_func => :directory?)
+          remove(metadata_file, :checker_func => :file?)
+          remove(sass_cache, :checker_func => :directory?)
         end
 
         def remove(filename, checker_func: :file?)
diff --git a/lib/jekyll/commands/doctor.rb b/lib/jekyll/commands/doctor.rb
index 5c48d5be..0c4f52f8 100644
--- a/lib/jekyll/commands/doctor.rb
+++ b/lib/jekyll/commands/doctor.rb
@@ -4,11 +4,12 @@ module Jekyll
       class << self
         def init_with_program(prog)
           prog.command(:doctor) do |c|
-            c.syntax 'doctor'
-            c.description 'Search site and print specific deprecation warnings'
+            c.syntax "doctor"
+            c.description "Search site and print specific deprecation warnings"
             c.alias(:hyde)
 
-            c.option 'config', '--config CONFIG_FILE[,CONFIG_FILE2,...]', Array, 'Custom configuration file'
+            c.option "config", "--config CONFIG_FILE[,CONFIG_FILE2,...]", Array,
+                            "Custom configuration file"
 
             c.action do |_, options|
               Jekyll::Commands::Doctor.process(options)
@@ -37,7 +38,7 @@ module Jekyll
         end
 
         def deprecated_relative_permalinks(site)
-          if site.config['relative_permalinks']
+          if site.config["relative_permalinks"]
             Jekyll::Deprecator.deprecation_message "Your site still uses relative" \
                                 " permalinks, which was removed in" \
                                 " Jekyll v3.0.0."
@@ -78,7 +79,7 @@ module Jekyll
         def urls_only_differ_by_case(site)
           urls_only_differ_by_case = false
           urls = case_insensitive_urls(site.pages + site.docs_to_write, site.dest)
-          urls.each do |case_insensitive_url, real_urls|
+          urls.each do |_case_insensitive_url, real_urls|
             next unless real_urls.uniq.size > 1
             urls_only_differ_by_case = true
             Jekyll.logger.warn "Warning:", "The following URLs only differ" \
@@ -102,10 +103,9 @@ module Jekyll
         end
 
         def case_insensitive_urls(things, destination)
-          things.inject({}) do |memo, thing|
+          things.each_with_object({}) do |thing, memo|
             dest = thing.destination(destination)
             (memo[dest.downcase] ||= []) << dest
-            memo
           end
         end
       end
diff --git a/lib/jekyll/commands/help.rb b/lib/jekyll/commands/help.rb
index 01bf3280..b4f136bf 100644
--- a/lib/jekyll/commands/help.rb
+++ b/lib/jekyll/commands/help.rb
@@ -4,8 +4,8 @@ module Jekyll
       class << self
         def init_with_program(prog)
           prog.command(:help) do |c|
-            c.syntax 'help [subcommand]'
-            c.description 'Show the help message, optionally for a given subcommand.'
+            c.syntax "help [subcommand]"
+            c.description "Show the help message, optionally for a given subcommand."
 
             c.action do |args, _|
               cmd = (args.first || "").to_sym
@@ -22,7 +22,8 @@ module Jekyll
         end
 
         def invalid_command(prog, cmd)
-          Jekyll.logger.error "Error:", "Hmm... we don't know what the '#{cmd}' command is."
+          Jekyll.logger.error "Error:",
+                "Hmm... we don't know what the '#{cmd}' command is."
           Jekyll.logger.info  "Valid commands:", prog.commands.keys.join(", ")
         end
       end
diff --git a/lib/jekyll/commands/new.rb b/lib/jekyll/commands/new.rb
index 50838f41..2658383c 100644
--- a/lib/jekyll/commands/new.rb
+++ b/lib/jekyll/commands/new.rb
@@ -1,4 +1,4 @@
-require 'erb'
+require "erb"
 
 module Jekyll
   module Commands
@@ -6,11 +6,11 @@ module Jekyll
       class << self
         def init_with_program(prog)
           prog.command(:new) do |c|
-            c.syntax 'new PATH'
-            c.description 'Creates a new Jekyll site scaffold in PATH'
+            c.syntax "new PATH"
+            c.description "Creates a new Jekyll site scaffold in PATH"
 
-            c.option 'force', '--force', 'Force creation even if PATH already exists'
-            c.option 'blank', '--blank', 'Creates scaffolding but with empty files'
+            c.option "force", "--force", "Force creation even if PATH already exists"
+            c.option "blank", "--blank", "Creates scaffolding but with empty files"
 
             c.action do |args, options|
               Jekyll::Commands::New.process(args, options)
@@ -19,26 +19,19 @@ module Jekyll
         end
 
         def process(args, options = {})
-          raise ArgumentError.new('You must specify a path.') if args.empty?
+          raise ArgumentError, "You must specify a path." if args.empty?
 
           new_blog_path = File.expand_path(args.join(" "), Dir.pwd)
           FileUtils.mkdir_p new_blog_path
           if preserve_source_location?(new_blog_path, options)
-            Jekyll.logger.abort_with "Conflict:", "#{new_blog_path} exists and is not empty."
+            Jekyll.logger.abort_with "Conflict:",
+                      "#{new_blog_path} exists and is not empty."
           end
 
           if options["blank"]
             create_blank_site new_blog_path
           else
-            create_sample_files new_blog_path
-
-            File.open(File.expand_path(initialized_post_name, new_blog_path), "w") do |f|
-              f.write(scaffold_post_content)
-            end
-
-            File.open(File.expand_path("Gemfile", new_blog_path), "w") do |f|
-              f.write(gemfile_contents)
-            end
+            create_site new_blog_path
           end
 
           Jekyll.logger.info "New jekyll site installed in #{new_blog_path}."
@@ -59,7 +52,7 @@ module Jekyll
         #
         # Returns the filename of the sample post, as a String
         def initialized_post_name
-          "_posts/#{Time.now.strftime('%Y-%m-%d')}-welcome-to-jekyll.markdown"
+          "_posts/#{Time.now.strftime("%Y-%m-%d")}-welcome-to-jekyll.markdown"
         end
 
         private
@@ -90,12 +83,24 @@ gem "jekyll", "#{Jekyll::VERSION}"
 RUBY
         end
 
+        def create_site(new_blog_path)
+          create_sample_files new_blog_path
+
+          File.open(File.expand_path(initialized_post_name, new_blog_path), "w") do |f|
+            f.write(scaffold_post_content)
+          end
+
+          File.open(File.expand_path("Gemfile", new_blog_path), "w") do |f|
+            f.write(gemfile_contents)
+          end
+        end
+
         def preserve_source_location?(path, options)
           !options["force"] && !Dir["#{path}/**/*"].empty?
         end
 
         def create_sample_files(path)
-          FileUtils.cp_r site_template + '/.', path
+          FileUtils.cp_r site_template + "/.", path
           FileUtils.rm File.expand_path(scaffold_path, path)
         end
 
diff --git a/lib/jekyll/commands/serve.rb b/lib/jekyll/commands/serve.rb
index 1482dbed..8c633397 100644
--- a/lib/jekyll/commands/serve.rb
+++ b/lib/jekyll/commands/serve.rb
@@ -14,7 +14,7 @@ module Jekyll
             "Show a directory listing instead of loading your index file."],
           "skip_initial_build" => ["skip_initial_build", "--skip-initial-build",
             "Skips the initial site build which occurs before the server is started."]
-        }
+        }.freeze
 
         #
 
@@ -93,7 +93,7 @@ module Jekyll
             )
           }
 
-          opts[:DirectoryIndex] = [] if opts[:JekyllOptions]['show_dir_listing']
+          opts[:DirectoryIndex] = [] if opts[:JekyllOptions]["show_dir_listing"]
 
           enable_ssl(opts)
           enable_logging(opts)
@@ -107,7 +107,7 @@ module Jekyll
           WEBrick::Config::FileHandler.merge({
             :FancyIndexing     => true,
             :NondisclosureName => [
-              '.ht*', '~*'
+              ".ht*", "~*"
             ]
           })
         end
@@ -116,12 +116,12 @@ module Jekyll
 
         private
         def server_address(server, opts)
-          "%{prefix}://%{address}:%{port}%{baseurl}" % {
+          format("%{prefix}://%{address}:%{port}%{baseurl}", {
             :prefix => server.config[:SSLEnable] ? "https" : "http",
             :baseurl => opts["baseurl"] ? "#{opts["baseurl"]}/" : "",
             :address => server.config[:BindAddress],
             :port => server.config[:Port]
-          }
+          })
         end
 
         #
@@ -171,22 +171,27 @@ module Jekyll
         # forget to add one of the certificates.
 
         private
+        # rubocop:disable Metrics/AbcSize
         def enable_ssl(opts)
           return if !opts[:JekyllOptions]["ssl_cert"] && !opts[:JekyllOptions]["ssl_key"]
           if !opts[:JekyllOptions]["ssl_cert"] || !opts[:JekyllOptions]["ssl_key"]
+            # rubocop:disable Style/RedundantException
             raise RuntimeError, "--ssl-cert or --ssl-key missing."
           end
-
           require "openssl"
           require "webrick/https"
-          source_key = Jekyll.sanitized_path(opts[:JekyllOptions]["source"], opts[:JekyllOptions]["ssl_key" ])
-          source_certificate = Jekyll.sanitized_path(opts[:JekyllOptions]["source"], opts[:JekyllOptions]["ssl_cert"])
-          opts[:SSLCertificate] = OpenSSL::X509::Certificate.new(File.read(source_certificate))
+          source_key = Jekyll.sanitized_path(opts[:JekyllOptions]["source"], \
+                    opts[:JekyllOptions]["ssl_key" ])
+          source_certificate = Jekyll.sanitized_path(opts[:JekyllOptions]["source"], \
+                    opts[:JekyllOptions]["ssl_cert"])
+          opts[:SSLCertificate] =
+            OpenSSL::X509::Certificate.new(File.read(source_certificate))
           opts[:SSLPrivateKey ] = OpenSSL::PKey::RSA.new(File.read(source_key))
           opts[:SSLEnable] = true
         end
 
         private
+
         def start_callback(detached)
           unless detached
             proc do
@@ -197,7 +202,7 @@ module Jekyll
 
         private
         def mime_types
-          file = File.expand_path('../mime.types', File.dirname(__FILE__))
+          file = File.expand_path("../mime.types", File.dirname(__FILE__))
           WEBrick::HTTPUtils.load_mime_types(file)
         end
       end
diff --git a/lib/jekyll/commands/serve/servlet.rb b/lib/jekyll/commands/serve/servlet.rb
index bb4afe5a..5f258e6e 100644
--- a/lib/jekyll/commands/serve/servlet.rb
+++ b/lib/jekyll/commands/serve/servlet.rb
@@ -7,7 +7,7 @@ module Jekyll
         DEFAULTS = {
           "Cache-Control" => "private, max-age=0, proxy-revalidate, " \
             "no-store, no-cache, must-revalidate"
-        }
+        }.freeze
 
         def initialize(server, root, callbacks)
           # So we can access them easily.
@@ -25,8 +25,7 @@ module Jekyll
           super || super(req, res, "#{basename}.html")
         end
 
-        #
-
+        # rubocop:disable Style/MethodName
         def do_GET(req, res)
           rtn = super
           validate_and_ensure_charset(req, res)