diff --git a/Library/Homebrew/cask/lib/hbc/artifact/abstract_flight_block.rb b/Library/Homebrew/cask/lib/hbc/artifact/abstract_flight_block.rb
index 30709a0b5d..be3050acb7 100644
--- a/Library/Homebrew/cask/lib/hbc/artifact/abstract_flight_block.rb
+++ b/Library/Homebrew/cask/lib/hbc/artifact/abstract_flight_block.rb
@@ -4,7 +4,7 @@ module Hbc
   module Artifact
     class AbstractFlightBlock < Base
       def self.artifact_dsl_key
-        super.to_s.sub(%r{_block$}, "").to_sym
+        super.to_s.sub(/_block$/, "").to_sym
       end
 
       def self.uninstall_artifact_dsl_key
diff --git a/Library/Homebrew/cask/lib/hbc/artifact/base.rb b/Library/Homebrew/cask/lib/hbc/artifact/base.rb
index 141ab68810..05dbedd8fc 100644
--- a/Library/Homebrew/cask/lib/hbc/artifact/base.rb
+++ b/Library/Homebrew/cask/lib/hbc/artifact/base.rb
@@ -2,15 +2,15 @@ module Hbc
   module Artifact
     class Base
       def self.artifact_name
-        @artifact_name ||= name.sub(%r{^.*:}, "").gsub(%r{(.)([A-Z])}, '\1_\2').downcase
+        @artifact_name ||= name.sub(/^.*:/, "").gsub(/(.)([A-Z])/, '\1_\2').downcase
       end
 
       def self.artifact_english_name
-        @artifact_english_name ||= name.sub(%r{^.*:}, "").gsub(%r{(.)([A-Z])}, '\1 \2')
+        @artifact_english_name ||= name.sub(/^.*:/, "").gsub(/(.)([A-Z])/, '\1 \2')
       end
 
       def self.artifact_english_article
-        @artifact_english_article ||= artifact_english_name =~ %r{^[aeiou]}i ? "an" : "a"
+        @artifact_english_article ||= artifact_english_name =~ /^[aeiou]/i ? "an" : "a"
       end
 
       def self.artifact_dsl_key
diff --git a/Library/Homebrew/cask/lib/hbc/artifact/relocated.rb b/Library/Homebrew/cask/lib/hbc/artifact/relocated.rb
index 1b5a4ff474..335d7e2fcc 100644
--- a/Library/Homebrew/cask/lib/hbc/artifact/relocated.rb
+++ b/Library/Homebrew/cask/lib/hbc/artifact/relocated.rb
@@ -15,7 +15,7 @@ module Hbc
       attr_reader :source, :target
 
       def printable_target
-        target.to_s.sub(%r{^#{ENV['HOME']}(#{File::SEPARATOR}|$)}, "~/")
+        target.to_s.sub(/^#{ENV['HOME']}(#{File::SEPARATOR}|$)/, "~/")
       end
 
       ALT_NAME_ATTRIBUTE = "com.apple.metadata:kMDItemAlternateNames".freeze
@@ -28,7 +28,7 @@ module Hbc
         odebug "Adding #{ALT_NAME_ATTRIBUTE} metadata"
         altnames = @command.run("/usr/bin/xattr",
                                 args:         ["-p", ALT_NAME_ATTRIBUTE, file.to_s],
-                                print_stderr: false).stdout.sub(%r{\A\((.*)\)\Z}, '\1')
+                                print_stderr: false).stdout.sub(/\A\((.*)\)\Z/, '\1')
         odebug "Existing metadata is: '#{altnames}'"
         altnames.concat(", ") unless altnames.empty?
         altnames.concat(%Q{"#{altname}"})
diff --git a/Library/Homebrew/cask/lib/hbc/artifact/uninstall_base.rb b/Library/Homebrew/cask/lib/hbc/artifact/uninstall_base.rb
index 63ffd18c9c..b871cbc459 100644
--- a/Library/Homebrew/cask/lib/hbc/artifact/uninstall_base.rb
+++ b/Library/Homebrew/cask/lib/hbc/artifact/uninstall_base.rb
@@ -103,7 +103,7 @@ module Hbc
           ohai "Removing launchctl service #{service}"
           [false, true].each do |with_sudo|
             plist_status = @command.run("/bin/launchctl", args: ["list", service], sudo: with_sudo, print_stderr: false).stdout
-            if plist_status =~ %r{^\{}
+            if plist_status =~ /^\{/
               @command.run!("/bin/launchctl", args: ["remove", service], sudo: with_sudo)
               sleep 1
             end
@@ -164,8 +164,8 @@ module Hbc
         pid_string = @command.run!("/usr/bin/osascript",
                                    args: ["-e", %Q{tell application "System Events" to get the unix id of every process whose bundle identifier is "#{bundle_id}"}],
                                    sudo: true).stdout.chomp
-        return [] unless pid_string =~ %r{\A\d+(?:\s*,\s*\d+)*\Z} # sanity check
-        pid_string.split(%r{\s*,\s*}).map(&:strip).map(&:to_i)
+        return [] unless pid_string =~ /\A\d+(?:\s*,\s*\d+)*\Z/ # sanity check
+        pid_string.split(/\s*,\s*/).map(&:strip).map(&:to_i)
       end
 
       def uninstall_login_item(directives)
diff --git a/Library/Homebrew/cask/lib/hbc/audit.rb b/Library/Homebrew/cask/lib/hbc/audit.rb
index 533ede70d9..0cb4703701 100644
--- a/Library/Homebrew/cask/lib/hbc/audit.rb
+++ b/Library/Homebrew/cask/lib/hbc/audit.rb
@@ -84,7 +84,7 @@ module Hbc
     def check_sha256_actually_256(sha256: cask.sha256, stanza: "sha256")
       odebug "Verifying #{stanza} string is a legal SHA-256 digest"
       return unless sha256.is_a?(String)
-      return if sha256.length == 64 && sha256[%r{^[0-9a-f]+$}i]
+      return if sha256.length == 64 && sha256[/^[0-9a-f]+$/i]
       add_error "#{stanza} string must be of 64 hexadecimal characters"
     end
 
@@ -162,7 +162,7 @@ module Hbc
     end
 
     def bad_sourceforge_url?
-      bad_url_format?(%r{sourceforge},
+      bad_url_format?(/sourceforge/,
                       [
                         %r{\Ahttps://sourceforge\.net/projects/[^/]+/files/latest/download\Z},
                         %r{\Ahttps://downloads\.sourceforge\.net/(?!(project|sourceforge)\/)},
@@ -174,7 +174,7 @@ module Hbc
     end
 
     def bad_osdn_url?
-      bad_url_format?(%r{osd}, [%r{\Ahttps?://([^/]+.)?dl\.osdn\.jp/}])
+      bad_url_format?(/osd/, [%r{\Ahttps?://([^/]+.)?dl\.osdn\.jp/}])
     end
 
     def check_generic_artifacts
diff --git a/Library/Homebrew/cask/lib/hbc/cache.rb b/Library/Homebrew/cask/lib/hbc/cache.rb
index db3ec536b9..e343da3faf 100644
--- a/Library/Homebrew/cask/lib/hbc/cache.rb
+++ b/Library/Homebrew/cask/lib/hbc/cache.rb
@@ -17,7 +17,7 @@ module Hbc
         file = symlink.readlink
 
         new_name = file.basename
-                       .sub(%r{\-((?:(\d|#{DSL::Version::DIVIDER_REGEX})*\-\2*)*[^\-]+)$}x,
+                       .sub(/\-((?:(\d|#{DSL::Version::DIVIDER_REGEX})*\-\2*)*[^\-]+)$/x,
                             '--\1')
 
         renamed_file = Hbc.cache.join(new_name)
diff --git a/Library/Homebrew/cask/lib/hbc/caveats.rb b/Library/Homebrew/cask/lib/hbc/caveats.rb
index a854291513..983d288748 100644
--- a/Library/Homebrew/cask/lib/hbc/caveats.rb
+++ b/Library/Homebrew/cask/lib/hbc/caveats.rb
@@ -8,7 +8,7 @@ module Hbc
       dsl = DSL::Caveats.new(cask)
       retval = dsl.instance_eval(&@block)
       return if retval.nil?
-      puts retval.to_s.sub(%r{[\r\n \t]*\Z}, "\n\n")
+      puts retval.to_s.sub(/[\r\n \t]*\Z/, "\n\n")
     end
   end
 end
diff --git a/Library/Homebrew/cask/lib/hbc/cli.rb b/Library/Homebrew/cask/lib/hbc/cli.rb
index 11f8cc7167..cd12ab0860 100644
--- a/Library/Homebrew/cask/lib/hbc/cli.rb
+++ b/Library/Homebrew/cask/lib/hbc/cli.rb
@@ -129,7 +129,7 @@ module Hbc
         exec "brewcask-#{command}", *ARGV[1..-1]
       elsif Pathname.new(command.to_s).executable? &&
             command.to_s.include?("/") &&
-            !command.to_s.match(%r{\.rb$})
+            !command.to_s.match(/\.rb$/)
         # arbitrary external executable with literal path, useful
         # for development and troubleshooting
         exec command, *ARGV[1..-1]
@@ -163,7 +163,7 @@ module Hbc
       cask_taps = {}
       cask_list.each do |c|
         user, repo, token = c.split "/"
-        repo.sub!(%r{^homebrew-}i, "")
+        repo.sub!(/^homebrew-/i, "")
         cask_taps[token] ||= []
         cask_taps[token].push "#{user}/#{repo}"
       end
diff --git a/Library/Homebrew/cask/lib/hbc/cli/base.rb b/Library/Homebrew/cask/lib/hbc/cli/base.rb
index 6c706d5379..e218a47dd2 100644
--- a/Library/Homebrew/cask/lib/hbc/cli/base.rb
+++ b/Library/Homebrew/cask/lib/hbc/cli/base.rb
@@ -2,7 +2,7 @@ module Hbc
   class CLI
     class Base
       def self.command_name
-        @command_name ||= name.sub(%r{^.*:}, "").gsub(%r{(.)([A-Z])}, '\1_\2').downcase
+        @command_name ||= name.sub(/^.*:/, "").gsub(/(.)([A-Z])/, '\1_\2').downcase
       end
 
       def self.visible
diff --git a/Library/Homebrew/cask/lib/hbc/cli/cat.rb b/Library/Homebrew/cask/lib/hbc/cli/cat.rb
index 75f6c1e91e..464e23a5e4 100644
--- a/Library/Homebrew/cask/lib/hbc/cli/cat.rb
+++ b/Library/Homebrew/cask/lib/hbc/cli/cat.rb
@@ -5,7 +5,7 @@ module Hbc
         cask_tokens = cask_tokens_from(args)
         raise CaskUnspecifiedError if cask_tokens.empty?
         # only respects the first argument
-        cask_token = cask_tokens.first.sub(%r{\.rb$}i, "")
+        cask_token = cask_tokens.first.sub(/\.rb$/i, "")
         cask_path = Hbc.path(cask_token)
         raise CaskUnavailableError, cask_token.to_s unless cask_path.exist?
         puts File.open(cask_path, &:read)
diff --git a/Library/Homebrew/cask/lib/hbc/cli/create.rb b/Library/Homebrew/cask/lib/hbc/cli/create.rb
index 84537cdc13..3e2b9c1911 100644
--- a/Library/Homebrew/cask/lib/hbc/cli/create.rb
+++ b/Library/Homebrew/cask/lib/hbc/cli/create.rb
@@ -4,7 +4,7 @@ module Hbc
       def self.run(*args)
         cask_tokens = cask_tokens_from(args)
         raise CaskUnspecifiedError if cask_tokens.empty?
-        cask_token = cask_tokens.first.sub(%r{\.rb$}i, "")
+        cask_token = cask_tokens.first.sub(/\.rb$/i, "")
         cask_path = Hbc.path(cask_token)
         odebug "Creating Cask #{cask_token}"
 
diff --git a/Library/Homebrew/cask/lib/hbc/cli/doctor.rb b/Library/Homebrew/cask/lib/hbc/cli/doctor.rb
index e36999200d..873ca47fde 100644
--- a/Library/Homebrew/cask/lib/hbc/cli/doctor.rb
+++ b/Library/Homebrew/cask/lib/hbc/cli/doctor.rb
@@ -53,7 +53,7 @@ module Hbc
                                                      args:         %w[config --get remote.origin.url],
                                                      print_stderr: false).stdout.strip
           end
-          if homebrew_origin !~ %r{\S}
+          if homebrew_origin !~ /\S/
             homebrew_origin = "#{none_string} #{error_string}"
           elsif homebrew_origin !~ %r{(mxcl|Homebrew)/(home)?brew(\.git)?\Z}
             homebrew_origin.concat " #{error_string "warning: nonstandard origin"}"
@@ -92,7 +92,7 @@ module Hbc
                                                               print_stderr: false)
                                                         .stdout
                                                         .strip
-          if @homebrew_constants[name] !~ %r{\S}
+          if @homebrew_constants[name] !~ /\S/
             @homebrew_constants[name] = "#{none_string} #{error_string}"
           end
           path = Pathname.new(@homebrew_constants[name])
@@ -104,7 +104,7 @@ module Hbc
       end
 
       def self.locale_variables
-        ENV.keys.grep(%r{^(?:LC_\S+|LANG|LANGUAGE)\Z}).collect { |v| %Q{#{v}="#{ENV[v]}"} }.sort.join("\n")
+        ENV.keys.grep(/^(?:LC_\S+|LANG|LANGUAGE)\Z/).collect { |v| %Q{#{v}="#{ENV[v]}"} }.sort.join("\n")
       end
 
       def self.privileged_uid
@@ -118,7 +118,7 @@ module Hbc
       end
 
       def self.legacy_tap_pattern
-        %r{phinze}
+        /phinze/
       end
 
       def self.notfound_string
diff --git a/Library/Homebrew/cask/lib/hbc/cli/edit.rb b/Library/Homebrew/cask/lib/hbc/cli/edit.rb
index 3090cf1960..a6ff342341 100644
--- a/Library/Homebrew/cask/lib/hbc/cli/edit.rb
+++ b/Library/Homebrew/cask/lib/hbc/cli/edit.rb
@@ -5,7 +5,7 @@ module Hbc
         cask_tokens = cask_tokens_from(args)
         raise CaskUnspecifiedError if cask_tokens.empty?
         # only respects the first argument
-        cask_token = cask_tokens.first.sub(%r{\.rb$}i, "")
+        cask_token = cask_tokens.first.sub(/\.rb$/i, "")
         cask_path = Hbc.path(cask_token)
         odebug "Opening editor for Cask #{cask_token}"
         unless cask_path.exist?
diff --git a/Library/Homebrew/cask/lib/hbc/cli/internal_audit_modified_casks.rb b/Library/Homebrew/cask/lib/hbc/cli/internal_audit_modified_casks.rb
index 47258a7b2e..feb5a830a6 100644
--- a/Library/Homebrew/cask/lib/hbc/cli/internal_audit_modified_casks.rb
+++ b/Library/Homebrew/cask/lib/hbc/cli/internal_audit_modified_casks.rb
@@ -10,7 +10,7 @@ module Hbc
 
         def run(*args)
           commit_range = commit_range(args)
-          cleanup = args.any? { |a| a =~ %r{^-+c(leanup)?$}i }
+          cleanup = args.any? { |a| a =~ /^-+c(leanup)?$/i }
           new(commit_range, cleanup: cleanup).run
         end
 
@@ -109,7 +109,7 @@ module Hbc
 
       def relevant_stanza_modified?(cask_file)
         out = git("diff", commit_range, "--", cask_file)
-        out =~ %r{^\+\s*(#{RELEVANT_STANZAS.join('|')})}
+        out =~ /^\+\s*(#{RELEVANT_STANZAS.join('|')})/
       end
 
       def git(*args)
diff --git a/Library/Homebrew/cask/lib/hbc/cli/internal_use_base.rb b/Library/Homebrew/cask/lib/hbc/cli/internal_use_base.rb
index 96b6eeaa8f..b1f9c5631f 100644
--- a/Library/Homebrew/cask/lib/hbc/cli/internal_use_base.rb
+++ b/Library/Homebrew/cask/lib/hbc/cli/internal_use_base.rb
@@ -2,7 +2,7 @@ module Hbc
   class CLI
     class InternalUseBase < Base
       def self.command_name
-        super.sub(%r{^internal_}i, "_")
+        super.sub(/^internal_/i, "_")
       end
 
       def self.visible
diff --git a/Library/Homebrew/cask/lib/hbc/cli/search.rb b/Library/Homebrew/cask/lib/hbc/cli/search.rb
index 147e6d1949..8e8f8fd750 100644
--- a/Library/Homebrew/cask/lib/hbc/cli/search.rb
+++ b/Library/Homebrew/cask/lib/hbc/cli/search.rb
@@ -21,12 +21,12 @@ module Hbc
         all_tokens = CLI.nice_listing(Hbc.all_tokens)
         if search_regexp
           search_term = arguments.first
-          partial_matches = all_tokens.grep(%r{#{search_regexp}}i)
+          partial_matches = all_tokens.grep(/#{search_regexp}/i)
         else
-          simplified_tokens = all_tokens.map { |t| t.sub(%r{^.*\/}, "").gsub(%r{[^a-z0-9]+}i, "") }
-          simplified_search_term = search_term.sub(%r{\.rb$}i, "").gsub(%r{[^a-z0-9]+}i, "")
-          exact_match = simplified_tokens.grep(%r{^#{simplified_search_term}$}i) { |t| all_tokens[simplified_tokens.index(t)] }.first
-          partial_matches = simplified_tokens.grep(%r{#{simplified_search_term}}i) { |t| all_tokens[simplified_tokens.index(t)] }
+          simplified_tokens = all_tokens.map { |t| t.sub(%r{^.*\/}, "").gsub(/[^a-z0-9]+/i, "") }
+          simplified_search_term = search_term.sub(/\.rb$/i, "").gsub(/[^a-z0-9]+/i, "")
+          exact_match = simplified_tokens.grep(/^#{simplified_search_term}$/i) { |t| all_tokens[simplified_tokens.index(t)] }.first
+          partial_matches = simplified_tokens.grep(/#{simplified_search_term}/i) { |t| all_tokens[simplified_tokens.index(t)] }
           partial_matches.delete(exact_match)
         end
         [exact_match, partial_matches, search_term]
diff --git a/Library/Homebrew/cask/lib/hbc/cli/style.rb b/Library/Homebrew/cask/lib/hbc/cli/style.rb
index 0dd4bc4742..fcb59230ef 100644
--- a/Library/Homebrew/cask/lib/hbc/cli/style.rb
+++ b/Library/Homebrew/cask/lib/hbc/cli/style.rb
@@ -67,7 +67,7 @@ module Hbc
       end
 
       def fix?
-        args.any? { |arg| arg =~ %r{--(fix|(auto-?)?correct)} }
+        args.any? { |arg| arg =~ /--(fix|(auto-?)?correct)/ }
       end
     end
   end
diff --git a/Library/Homebrew/cask/lib/hbc/container/bzip2.rb b/Library/Homebrew/cask/lib/hbc/container/bzip2.rb
index 81808071fe..9f2a59bb8a 100644
--- a/Library/Homebrew/cask/lib/hbc/container/bzip2.rb
+++ b/Library/Homebrew/cask/lib/hbc/container/bzip2.rb
@@ -6,7 +6,7 @@ module Hbc
   class Container
     class Bzip2 < Base
       def self.me?(criteria)
-        criteria.magic_number(%r{^BZh}n)
+        criteria.magic_number(/^BZh/n)
       end
 
       def extract
diff --git a/Library/Homebrew/cask/lib/hbc/container/cab.rb b/Library/Homebrew/cask/lib/hbc/container/cab.rb
index 7ae6b06325..52c13402ce 100644
--- a/Library/Homebrew/cask/lib/hbc/container/cab.rb
+++ b/Library/Homebrew/cask/lib/hbc/container/cab.rb
@@ -8,7 +8,7 @@ module Hbc
       def self.me?(criteria)
         cabextract = which("cabextract")
 
-        criteria.magic_number(%r{^MSCF}n) &&
+        criteria.magic_number(/^MSCF/n) &&
           !cabextract.nil? &&
           criteria.command.run(cabextract, args: ["-t", "--", criteria.path.to_s]).stderr.empty?
       end
diff --git a/Library/Homebrew/cask/lib/hbc/container/criteria.rb b/Library/Homebrew/cask/lib/hbc/container/criteria.rb
index 207c5f3cd4..66ecb8c874 100644
--- a/Library/Homebrew/cask/lib/hbc/container/criteria.rb
+++ b/Library/Homebrew/cask/lib/hbc/container/criteria.rb
@@ -9,7 +9,7 @@ module Hbc
       end
 
       def extension(regex)
-        path.extname.sub(%r{^\.}, "") =~ Regexp.new(regex.source, regex.options | Regexp::IGNORECASE)
+        path.extname.sub(/^\./, "") =~ Regexp.new(regex.source, regex.options | Regexp::IGNORECASE)
       end
 
       def magic_number(regex)
diff --git a/Library/Homebrew/cask/lib/hbc/container/gzip.rb b/Library/Homebrew/cask/lib/hbc/container/gzip.rb
index 7e4722a7f8..d3dd7b8fd0 100644
--- a/Library/Homebrew/cask/lib/hbc/container/gzip.rb
+++ b/Library/Homebrew/cask/lib/hbc/container/gzip.rb
@@ -6,7 +6,7 @@ module Hbc
   class Container
     class Gzip < Base
       def self.me?(criteria)
-        criteria.magic_number(%r{^\037\213}n)
+        criteria.magic_number(/^\037\213/n)
       end
 
       def extract
diff --git a/Library/Homebrew/cask/lib/hbc/container/lzma.rb b/Library/Homebrew/cask/lib/hbc/container/lzma.rb
index cca4d814b7..1221acfbc0 100644
--- a/Library/Homebrew/cask/lib/hbc/container/lzma.rb
+++ b/Library/Homebrew/cask/lib/hbc/container/lzma.rb
@@ -6,7 +6,7 @@ module Hbc
   class Container
     class Lzma < Base
       def self.me?(criteria)
-        criteria.magic_number(%r{^\]\000\000\200\000}n)
+        criteria.magic_number(/^\]\000\000\200\000/n)
       end
 
       def extract
diff --git a/Library/Homebrew/cask/lib/hbc/container/otf.rb b/Library/Homebrew/cask/lib/hbc/container/otf.rb
index 66222ad8d6..823d04f74e 100644
--- a/Library/Homebrew/cask/lib/hbc/container/otf.rb
+++ b/Library/Homebrew/cask/lib/hbc/container/otf.rb
@@ -4,7 +4,7 @@ module Hbc
   class Container
     class Otf < Naked
       def self.me?(criteria)
-        criteria.magic_number(%r{^OTTO}n)
+        criteria.magic_number(/^OTTO/n)
       end
     end
   end
diff --git a/Library/Homebrew/cask/lib/hbc/container/pkg.rb b/Library/Homebrew/cask/lib/hbc/container/pkg.rb
index dfd62a8633..b5f5daad84 100644
--- a/Library/Homebrew/cask/lib/hbc/container/pkg.rb
+++ b/Library/Homebrew/cask/lib/hbc/container/pkg.rb
@@ -4,9 +4,9 @@ module Hbc
   class Container
     class Pkg < Naked
       def self.me?(criteria)
-        criteria.extension(%r{m?pkg$}) &&
+        criteria.extension(/m?pkg$/) &&
           (criteria.path.directory? ||
-           criteria.magic_number(%r{^xar!}n))
+           criteria.magic_number(/^xar!/n))
       end
     end
   end
diff --git a/Library/Homebrew/cask/lib/hbc/container/rar.rb b/Library/Homebrew/cask/lib/hbc/container/rar.rb
index bcf225623b..81481f84bd 100644
--- a/Library/Homebrew/cask/lib/hbc/container/rar.rb
+++ b/Library/Homebrew/cask/lib/hbc/container/rar.rb
@@ -4,7 +4,7 @@ module Hbc
   class Container
     class Rar < GenericUnar
       def self.me?(criteria)
-        criteria.magic_number(%r{^Rar!}n) &&
+        criteria.magic_number(/^Rar!/n) &&
           super
       end
     end
diff --git a/Library/Homebrew/cask/lib/hbc/container/seven_zip.rb b/Library/Homebrew/cask/lib/hbc/container/seven_zip.rb
index 7a144d5327..d1839907cd 100644
--- a/Library/Homebrew/cask/lib/hbc/container/seven_zip.rb
+++ b/Library/Homebrew/cask/lib/hbc/container/seven_zip.rb
@@ -5,7 +5,7 @@ module Hbc
     class SevenZip < GenericUnar
       def self.me?(criteria)
         # TODO: cover self-extracting archives
-        criteria.magic_number(%r{^7z}n) &&
+        criteria.magic_number(/^7z/n) &&
           super
       end
     end
diff --git a/Library/Homebrew/cask/lib/hbc/container/sit.rb b/Library/Homebrew/cask/lib/hbc/container/sit.rb
index 2d88493994..c486a981c3 100644
--- a/Library/Homebrew/cask/lib/hbc/container/sit.rb
+++ b/Library/Homebrew/cask/lib/hbc/container/sit.rb
@@ -4,7 +4,7 @@ module Hbc
   class Container
     class Sit < GenericUnar
       def self.me?(criteria)
-        criteria.magic_number(%r{^StuffIt}n) &&
+        criteria.magic_number(/^StuffIt/n) &&
           super
       end
     end
diff --git a/Library/Homebrew/cask/lib/hbc/container/tar.rb b/Library/Homebrew/cask/lib/hbc/container/tar.rb
index df77e454d0..eb646c816f 100644
--- a/Library/Homebrew/cask/lib/hbc/container/tar.rb
+++ b/Library/Homebrew/cask/lib/hbc/container/tar.rb
@@ -6,7 +6,7 @@ module Hbc
   class Container
     class Tar < Base
       def self.me?(criteria)
-        criteria.magic_number(%r{^.{257}ustar}n) ||
+        criteria.magic_number(/^.{257}ustar/n) ||
           # or compressed tar (bzip2/gzip/lzma/xz)
           IO.popen(["/usr/bin/tar", "-t", "-f", criteria.path.to_s], err: "/dev/null") { |io| !io.read(1).nil? }
       end
diff --git a/Library/Homebrew/cask/lib/hbc/container/ttf.rb b/Library/Homebrew/cask/lib/hbc/container/ttf.rb
index 62ca29b223..612a804f95 100644
--- a/Library/Homebrew/cask/lib/hbc/container/ttf.rb
+++ b/Library/Homebrew/cask/lib/hbc/container/ttf.rb
@@ -5,9 +5,9 @@ module Hbc
     class Ttf < Naked
       def self.me?(criteria)
         # TrueType Font
-        criteria.magic_number(%r{^\000\001\000\000\000}n) ||
+        criteria.magic_number(/^\000\001\000\000\000/n) ||
           # Truetype Font Collection
-          criteria.magic_number(%r{^ttcf}n)
+          criteria.magic_number(/^ttcf/n)
       end
     end
   end
diff --git a/Library/Homebrew/cask/lib/hbc/container/xar.rb b/Library/Homebrew/cask/lib/hbc/container/xar.rb
index 228ab23435..a0165ca57e 100644
--- a/Library/Homebrew/cask/lib/hbc/container/xar.rb
+++ b/Library/Homebrew/cask/lib/hbc/container/xar.rb
@@ -6,7 +6,7 @@ module Hbc
   class Container
     class Xar < Base
       def self.me?(criteria)
-        criteria.magic_number(%r{^xar!}n)
+        criteria.magic_number(/^xar!/n)
       end
 
       def extract
diff --git a/Library/Homebrew/cask/lib/hbc/container/xip.rb b/Library/Homebrew/cask/lib/hbc/container/xip.rb
index 2d0f17e2e8..982402e4e6 100644
--- a/Library/Homebrew/cask/lib/hbc/container/xip.rb
+++ b/Library/Homebrew/cask/lib/hbc/container/xip.rb
@@ -4,8 +4,8 @@ module Hbc
   class Container
     class Xip < Base
       def self.me?(criteria)
-        criteria.magic_number(%r{^xar!}n) &&
-          IO.popen(["/usr/bin/xar", "-t", "-f", criteria.path.to_s], err: "/dev/null") { |io| io.read =~ %r{\AContent\nMetadata\n\Z} }
+        criteria.magic_number(/^xar!/n) &&
+          IO.popen(["/usr/bin/xar", "-t", "-f", criteria.path.to_s], err: "/dev/null") { |io| io.read =~ /\AContent\nMetadata\n\Z/ }
       end
 
       def extract
diff --git a/Library/Homebrew/cask/lib/hbc/container/xz.rb b/Library/Homebrew/cask/lib/hbc/container/xz.rb
index fc0ae064e8..cd9f9aee2f 100644
--- a/Library/Homebrew/cask/lib/hbc/container/xz.rb
+++ b/Library/Homebrew/cask/lib/hbc/container/xz.rb
@@ -6,7 +6,7 @@ module Hbc
   class Container
     class Xz < Base
       def self.me?(criteria)
-        criteria.magic_number(%r{^\xFD7zXZ\x00}n)
+        criteria.magic_number(/^\xFD7zXZ\x00/n)
       end
 
       def extract
diff --git a/Library/Homebrew/cask/lib/hbc/container/zip.rb b/Library/Homebrew/cask/lib/hbc/container/zip.rb
index 86e2d1bd69..8e3cf5b2dc 100644
--- a/Library/Homebrew/cask/lib/hbc/container/zip.rb
+++ b/Library/Homebrew/cask/lib/hbc/container/zip.rb
@@ -4,7 +4,7 @@ module Hbc
   class Container
     class Zip < Base
       def self.me?(criteria)
-        criteria.magic_number(%r{^PK(\003\004|\005\006)}n)
+        criteria.magic_number(/^PK(\003\004|\005\006)/n)
       end
 
       def extract
diff --git a/Library/Homebrew/cask/lib/hbc/download_strategy.rb b/Library/Homebrew/cask/lib/hbc/download_strategy.rb
index 400b9ffc87..1d22e2ed2a 100644
--- a/Library/Homebrew/cask/lib/hbc/download_strategy.rb
+++ b/Library/Homebrew/cask/lib/hbc/download_strategy.rb
@@ -74,7 +74,7 @@ module Hbc
     end
 
     def temporary_path
-      @temporary_path ||= tarball_path.sub(%r{$}, ".incomplete")
+      @temporary_path ||= tarball_path.sub(/$/, ".incomplete")
     end
 
     def cached_location
@@ -216,7 +216,7 @@ module Hbc
     end
 
     def repo_url
-      `svn info '#{@clone}' 2>/dev/null`.strip[%r{^URL: (.+)$}, 1]
+      `svn info '#{@clone}' 2>/dev/null`.strip[/^URL: (.+)$/, 1]
     end
 
     # super does not provide checks for already-existing downloads
@@ -224,7 +224,7 @@ module Hbc
       if tarball_path.exist?
         puts "Already downloaded: #{tarball_path}"
       else
-        @url = @url.sub(%r{^svn\+}, "") if @url =~ %r{^svn\+http://}
+        @url = @url.sub(/^svn\+/, "") if @url =~ %r{^svn\+http://}
         ohai "Checking out #{@url}"
 
         clear_cache unless @url.chomp("/") == repo_url || quiet_system("svn", "switch", @url, @clone)
@@ -291,12 +291,12 @@ module Hbc
     def shell_quote(str)
       # Oh god escaping shell args.
       # See http://notetoself.vrensk.com/2008/08/escaping-single-quotes-in-ruby-harder-than-expected/
-      str.gsub(%r{\\|'}) { |c| "\\#{c}" }
+      str.gsub(/\\|'/) { |c| "\\#{c}" }
     end
 
     def fetch_externals
       `svn propget svn:externals '#{shell_quote(@url)}'`.chomp.each_line do |line|
-        name, url = line.split(%r{\s+})
+        name, url = line.split(/\s+/)
         yield name, url
       end
     end
diff --git a/Library/Homebrew/cask/lib/hbc/dsl.rb b/Library/Homebrew/cask/lib/hbc/dsl.rb
index ff0db0040d..1ae9a0c4df 100644
--- a/Library/Homebrew/cask/lib/hbc/dsl.rb
+++ b/Library/Homebrew/cask/lib/hbc/dsl.rb
@@ -252,7 +252,7 @@ module Hbc
       if block_given?
         @caveats << Hbc::Caveats.new(block)
       elsif string.any?
-        @caveats << string.map { |s| s.to_s.sub(%r{[\r\n \t]*\Z}, "\n\n") }
+        @caveats << string.map { |s| s.to_s.sub(/[\r\n \t]*\Z/, "\n\n") }
       end
       @caveats
     end
diff --git a/Library/Homebrew/cask/lib/hbc/dsl/base.rb b/Library/Homebrew/cask/lib/hbc/dsl/base.rb
index 20a3cec619..63df847e95 100644
--- a/Library/Homebrew/cask/lib/hbc/dsl/base.rb
+++ b/Library/Homebrew/cask/lib/hbc/dsl/base.rb
@@ -16,7 +16,7 @@ module Hbc
 
       def method_missing(method, *)
         if method
-          underscored_class = self.class.name.gsub(%r{([[:lower:]])([[:upper:]][[:lower:]])}, '\1_\2').downcase
+          underscored_class = self.class.name.gsub(/([[:lower:]])([[:upper:]][[:lower:]])/, '\1_\2').downcase
           section = underscored_class.downcase.split("::").last
           Utils.method_missing_message(method, @cask.to_s, section)
           nil
diff --git a/Library/Homebrew/cask/lib/hbc/dsl/depends_on.rb b/Library/Homebrew/cask/lib/hbc/dsl/depends_on.rb
index 0e80938b78..f402c603cc 100644
--- a/Library/Homebrew/cask/lib/hbc/dsl/depends_on.rb
+++ b/Library/Homebrew/cask/lib/hbc/dsl/depends_on.rb
@@ -62,7 +62,7 @@ module Hbc
         begin
           if arg.is_a?(Symbol)
             Gem::Version.new(@macos_symbols.fetch(arg))
-          elsif arg =~ %r{^\s*:?([a-z]\S+)\s*$}i
+          elsif arg =~ /^\s*:?([a-z]\S+)\s*$/i
             Gem::Version.new(@macos_symbols.fetch(Regexp.last_match[1].downcase.to_sym))
           elsif @inverted_macos_symbols.key?(arg)
             Gem::Version.new(arg)
@@ -86,7 +86,7 @@ module Hbc
 
       def macos=(*arg)
         @macos ||= []
-        macos = if arg.count == 1 && arg.first =~ %r{^\s*(<|>|[=<>]=)\s*(\S+)\s*$}
+        macos = if arg.count == 1 && arg.first =~ /^\s*(<|>|[=<>]=)\s*(\S+)\s*$/
                   raise "'depends_on macos' comparison expressions cannot be combined" unless @macos.empty?
                   operator = Regexp.last_match[1].to_sym
                   release = self.class.coerce_os_release(Regexp.last_match[2])
@@ -103,7 +103,7 @@ module Hbc
       def arch=(*arg)
         @arch ||= []
         arches = Array(*arg).map { |elt|
-          elt = elt.to_s.downcase.sub(%r{^:}, "").tr("-", "_").to_sym
+          elt = elt.to_s.downcase.sub(/^:/, "").tr("-", "_").to_sym
           ARCH_SYNONYMS.key?(elt) ? ARCH_SYNONYMS[elt] : elt
         }
         invalid_arches = arches - VALID_ARCHES.keys
diff --git a/Library/Homebrew/cask/lib/hbc/dsl/gpg.rb b/Library/Homebrew/cask/lib/hbc/dsl/gpg.rb
index 572ede2279..c54db45247 100644
--- a/Library/Homebrew/cask/lib/hbc/dsl/gpg.rb
+++ b/Library/Homebrew/cask/lib/hbc/dsl/gpg.rb
@@ -28,7 +28,7 @@ module Hbc
 
       def valid_id?(id)
         legal_lengths = Set.new [8, 16, 40]
-        is_valid = id.is_a?(String) && legal_lengths.include?(id.length) && id[%r{^[0-9a-f]+$}i]
+        is_valid = id.is_a?(String) && legal_lengths.include?(id.length) && id[/^[0-9a-f]+$/i]
         raise "invalid ':key_id' value: '#{id.inspect}'" unless is_valid
 
         is_valid
diff --git a/Library/Homebrew/cask/lib/hbc/dsl/version.rb b/Library/Homebrew/cask/lib/hbc/dsl/version.rb
index d4697460af..63c15a02d1 100644
--- a/Library/Homebrew/cask/lib/hbc/dsl/version.rb
+++ b/Library/Homebrew/cask/lib/hbc/dsl/version.rb
@@ -8,9 +8,9 @@ module Hbc
                    "/" => :slashes,
                  }.freeze
 
-      DIVIDER_REGEX = %r{(#{DIVIDERS.keys.map { |v| Regexp.quote(v) }.join('|')})}
+      DIVIDER_REGEX = /(#{DIVIDERS.keys.map { |v| Regexp.quote(v) }.join('|')})/
 
-      MAJOR_MINOR_PATCH_REGEX = %r{^(\d+)(?:\.(\d+)(?:\.(\d+))?)?}
+      MAJOR_MINOR_PATCH_REGEX = /^(\d+)(?:\.(\d+)(?:\.(\d+))?)?/
 
       class << self
         private
diff --git a/Library/Homebrew/cask/lib/hbc/fetcher.rb b/Library/Homebrew/cask/lib/hbc/fetcher.rb
index 6f58ca0237..fb2b743fac 100644
--- a/Library/Homebrew/cask/lib/hbc/fetcher.rb
+++ b/Library/Homebrew/cask/lib/hbc/fetcher.rb
@@ -5,7 +5,7 @@ module Hbc
     TIMEOUT = 10
 
     def self.head(url)
-      if url.to_s =~ %r{googlecode}
+      if url.to_s =~ /googlecode/
         googlecode_fake_head(url)
       else
         SystemCommand.run("/usr/bin/curl",
@@ -18,7 +18,7 @@ module Hbc
     def self.googlecode_fake_head(url)
       command = "curl --max-time #{TIMEOUT} --verbose --location '#{url}' | head -n 20 > /dev/null"
       stderr = Open3.capture3(command)[1]
-      stderr.split("\n").grep(%r{^< }).map { |line| line.sub(%r{^< }, "") }.join("\n")
+      stderr.split("\n").grep(/^< /).map { |line| line.sub(/^< /, "") }.join("\n")
     end
   end
 end
diff --git a/Library/Homebrew/cask/lib/hbc/locations.rb b/Library/Homebrew/cask/lib/hbc/locations.rb
index f1c7d138be..099caf6658 100644
--- a/Library/Homebrew/cask/lib/hbc/locations.rb
+++ b/Library/Homebrew/cask/lib/hbc/locations.rb
@@ -136,7 +136,7 @@ module Hbc
         return query_path if query_path.absolute?
         return query_path if query_path.exist? && query_path.extname == ".rb"
 
-        query_without_extension = query.sub(%r{\.rb$}i, "")
+        query_without_extension = query.sub(/\.rb$/i, "")
 
         token_with_tap = if query =~ %r{\A[^/]+/[^/]+/[^/]+\Z}
                            query_without_extension
diff --git a/Library/Homebrew/cask/lib/hbc/qualified_token.rb b/Library/Homebrew/cask/lib/hbc/qualified_token.rb
index 7b2e93dcfb..8868bd65df 100644
--- a/Library/Homebrew/cask/lib/hbc/qualified_token.rb
+++ b/Library/Homebrew/cask/lib/hbc/qualified_token.rb
@@ -3,20 +3,20 @@ module Hbc
     REPO_PREFIX = "homebrew-".freeze
 
     # per https://github.com/Homebrew/homebrew/blob/4c7bc9ec3bca729c898ee347b6135ba692ee0274/Library/Homebrew/cmd/tap.rb#L121
-    USER_REGEX = %r{[a-z0-9_\-]+}
+    USER_REGEX = /[a-z0-9_\-]+/
 
     # per https://github.com/Homebrew/homebrew/blob/4c7bc9ec3bca729c898ee347b6135ba692ee0274/Library/Homebrew/cmd/tap.rb#L121
-    REPO_REGEX = %r{(?:#{REPO_PREFIX})?\w+}
+    REPO_REGEX = /(?:#{REPO_PREFIX})?\w+/
 
     # per https://github.com/caskroom/homebrew-cask/blob/master/CONTRIBUTING.md#generating-a-token-for-the-cask
-    TOKEN_REGEX = %r{[a-z0-9\-]+}
+    TOKEN_REGEX = /[a-z0-9\-]+/
 
     TAP_REGEX = %r{#{USER_REGEX}[/\-]#{REPO_REGEX}}
 
     QUALIFIED_TOKEN_REGEX = %r{#{TAP_REGEX}/#{TOKEN_REGEX}}
 
     def self.parse(arg)
-      return nil unless arg.is_a?(String) && arg.downcase =~ %r{^#{QUALIFIED_TOKEN_REGEX}$}
+      return nil unless arg.is_a?(String) && arg.downcase =~ /^#{QUALIFIED_TOKEN_REGEX}$/
       path_elements = arg.downcase.split("/")
       if path_elements.count == 2
         # eg phinze-cask/google-chrome.
@@ -31,7 +31,7 @@ module Hbc
         # per https://github.com/Homebrew/brew/blob/master/docs/brew-tap.md
         user, repo, token = path_elements
       end
-      repo.sub!(%r{^#{REPO_PREFIX}}, "")
+      repo.sub!(/^#{REPO_PREFIX}/, "")
       odebug "[user, repo, token] might be [#{user}, #{repo}, #{token}]"
       [user, repo, token]
     end
diff --git a/Library/Homebrew/cask/lib/hbc/source.rb b/Library/Homebrew/cask/lib/hbc/source.rb
index b4d105894d..ae1fdaf8ab 100644
--- a/Library/Homebrew/cask/lib/hbc/source.rb
+++ b/Library/Homebrew/cask/lib/hbc/source.rb
@@ -22,7 +22,7 @@ module Hbc
 
     def self.for_query(query)
       odebug "Translating '#{query}' into a valid Cask source"
-      raise CaskUnavailableError, query if query.to_s =~ %r{^\s*$}
+      raise CaskUnavailableError, query if query.to_s =~ /^\s*$/
       source = sources.find { |s|
         odebug "Testing source class #{s}"
         s.me?(query)
diff --git a/Library/Homebrew/cask/lib/hbc/source/path_base.rb b/Library/Homebrew/cask/lib/hbc/source/path_base.rb
index 7d68e518b4..4e4bdcf158 100644
--- a/Library/Homebrew/cask/lib/hbc/source/path_base.rb
+++ b/Library/Homebrew/cask/lib/hbc/source/path_base.rb
@@ -7,7 +7,7 @@ module Hbc
       # derived classes must define method self.me?
 
       def self.path_for_query(query)
-        Pathname.new(query).sub(%r{(\.rb)?$}, ".rb")
+        Pathname.new(query).sub(/(\.rb)?$/, ".rb")
       end
 
       attr_reader :path
diff --git a/Library/Homebrew/cask/lib/hbc/system_command.rb b/Library/Homebrew/cask/lib/hbc/system_command.rb
index aa4b9b2957..41fa924f91 100644
--- a/Library/Homebrew/cask/lib/hbc/system_command.rb
+++ b/Library/Homebrew/cask/lib/hbc/system_command.rb
@@ -144,7 +144,7 @@ module Hbc
       end
 
       def self._warn_plist_garbage(command, garbage)
-        return true unless garbage =~ %r{\S}
+        return true unless garbage =~ /\S/
         external = File.basename(command.first)
         lines = garbage.strip.split("\n")
         opoo "Non-XML stdout from #{external}:"
@@ -152,8 +152,8 @@ module Hbc
       end
 
       def self._parse_plist(command, output)
-        raise CaskError, "Empty plist input" unless output =~ %r{\S}
-        output.sub!(%r{\A(.*?)(<\?\s*xml)}m, '\2')
+        raise CaskError, "Empty plist input" unless output =~ /\S/
+        output.sub!(/\A(.*?)(<\?\s*xml)/m, '\2')
         _warn_plist_garbage(command, Regexp.last_match[1]) if Hbc.debug
         output.sub!(%r{(<\s*/\s*plist\s*>)(.*?)\Z}m, '\1')
         _warn_plist_garbage(command, Regexp.last_match[2])
diff --git a/Library/Homebrew/cask/lib/hbc/url_checker.rb b/Library/Homebrew/cask/lib/hbc/url_checker.rb
index 4dc1f136aa..6dfe0bebea 100644
--- a/Library/Homebrew/cask/lib/hbc/url_checker.rb
+++ b/Library/Homebrew/cask/lib/hbc/url_checker.rb
@@ -52,7 +52,7 @@ module Hbc
 
       case cask.url.scheme
       when "http", "https" then
-        @response_status = response_lines.grep(%r{^HTTP}).last
+        @response_status = response_lines.grep(/^HTTP/).last
         if @response_status.respond_to?(:strip)
           @response_status.strip!
           unless response_lines.index(@response_status).nil?
diff --git a/Library/Homebrew/cask/lib/hbc/utils.rb b/Library/Homebrew/cask/lib/hbc/utils.rb
index 38fa23463f..116cb20956 100644
--- a/Library/Homebrew/cask/lib/hbc/utils.rb
+++ b/Library/Homebrew/cask/lib/hbc/utils.rb
@@ -12,7 +12,7 @@ class Object
   def utf8_inspect
     return inspect unless defined?(Encoding)
     return map(&:utf8_inspect) if respond_to?(:map)
-    inspect.force_encoding("UTF-8").sub(%r{\A"(.*)"\Z}, '\1')
+    inspect.force_encoding("UTF-8").sub(/\A"(.*)"\Z/, '\1')
   end
 end
 
diff --git a/Library/Homebrew/cask/spec/cask/audit_spec.rb b/Library/Homebrew/cask/spec/cask/audit_spec.rb
index c5433d0a29..c12063a1d6 100644
--- a/Library/Homebrew/cask/spec/cask/audit_spec.rb
+++ b/Library/Homebrew/cask/spec/cask/audit_spec.rb
@@ -20,7 +20,7 @@ describe Hbc::Audit do
         audit.add_error "bad"
       end
 
-      it { is_expected.to match(%r{failed}) }
+      it { is_expected.to match(/failed/) }
     end
 
     context "when there are warnings" do
@@ -28,7 +28,7 @@ describe Hbc::Audit do
         audit.add_warning "eh"
       end
 
-      it { is_expected.to match(%r{warning}) }
+      it { is_expected.to match(/warning/) }
     end
 
     context "when there are errors and warnings" do
@@ -37,11 +37,11 @@ describe Hbc::Audit do
         audit.add_warning "eh"
       end
 
-      it { is_expected.to match(%r{failed}) }
+      it { is_expected.to match(/failed/) }
     end
 
     context "when there are no errors or warnings" do
-      it { is_expected.to match(%r{passed}) }
+      it { is_expected.to match(/passed/) }
     end
   end
 
@@ -53,7 +53,7 @@ describe Hbc::Audit do
       %w[version sha256 url name homepage].each do |stanza|
         context "when missing #{stanza}" do
           let(:cask_token) { "missing-#{stanza}" }
-          it { is_expected.to fail_with(%r{#{stanza} stanza is required}) }
+          it { is_expected.to fail_with(/#{stanza} stanza is required/) }
         end
       end
     end
@@ -85,36 +85,36 @@ describe Hbc::Audit do
 
       context "when sha256 is sha256 for empty string" do
         let(:cask_token) { "sha256-for-empty-string" }
-        it { is_expected.to fail_with(%r{cannot use the sha256 for an empty string}) }
+        it { is_expected.to fail_with(/cannot use the sha256 for an empty string/) }
       end
     end
 
     describe "appcast checks" do
       context "when appcast has no sha256" do
         let(:cask_token) { "appcast-missing-checkpoint" }
-        it { is_expected.to fail_with(%r{checkpoint sha256 is required for appcast}) }
+        it { is_expected.to fail_with(/checkpoint sha256 is required for appcast/) }
       end
 
       context "when appcast checkpoint is not a string of 64 hexadecimal characters" do
         let(:cask_token) { "appcast-invalid-checkpoint" }
-        it { is_expected.to fail_with(%r{string must be of 64 hexadecimal characters}) }
+        it { is_expected.to fail_with(/string must be of 64 hexadecimal characters/) }
       end
 
       context "when appcast checkpoint is sha256 for empty string" do
         let(:cask_token) { "appcast-checkpoint-sha256-for-empty-string" }
-        it { is_expected.to fail_with(%r{cannot use the sha256 for an empty string}) }
+        it { is_expected.to fail_with(/cannot use the sha256 for an empty string/) }
       end
 
       context "when appcast checkpoint is valid sha256" do
         let(:cask_token) { "appcast-valid-checkpoint" }
-        it { should_not fail_with(%r{appcast :checkpoint}) }
+        it { should_not fail_with(/appcast :checkpoint/) }
       end
 
       context "when verifying appcast HTTP code" do
         let(:cask_token) { "appcast-valid-checkpoint" }
         let(:download) { instance_double(Hbc::Download) }
-        let(:wrong_code_msg) { %r{unexpected HTTP response code} }
-        let(:curl_error_msg) { %r{error retrieving appcast} }
+        let(:wrong_code_msg) { /unexpected HTTP response code/ }
+        let(:curl_error_msg) { /error retrieving appcast/ }
         let(:fake_curl_result) { instance_double(Hbc::SystemCommand::Result) }
 
         before do
@@ -155,8 +155,8 @@ describe Hbc::Audit do
       context "when verifying appcast checkpoint" do
         let(:cask_token) { "appcast-valid-checkpoint" }
         let(:download) { instance_double(Hbc::Download) }
-        let(:mismatch_msg) { %r{appcast checkpoint mismatch} }
-        let(:curl_error_msg) { %r{error retrieving appcast} }
+        let(:mismatch_msg) { /appcast checkpoint mismatch/ }
+        let(:curl_error_msg) { /error retrieving appcast/ }
         let(:fake_curl_result) { instance_double(Hbc::SystemCommand::Result) }
         let(:expected_checkpoint) { "d5b2dfbef7ea28c25f7a77cd7fa14d013d82b626db1d82e00e25822464ba19e2" }
 
@@ -203,7 +203,7 @@ describe Hbc::Audit do
     end
 
     describe "preferred download URL formats" do
-      let(:warning_msg) { %r{URL format incorrect} }
+      let(:warning_msg) { /URL format incorrect/ }
 
       context "with incorrect SourceForge URL format" do
         let(:cask_token) { "sourceforge-incorrect-url-format" }
@@ -234,17 +234,17 @@ describe Hbc::Audit do
     describe "generic artifact checks" do
       context "with no target" do
         let(:cask_token) { "generic-artifact-no-target" }
-        it { is_expected.to fail_with(%r{target required for generic artifact}) }
+        it { is_expected.to fail_with(/target required for generic artifact/) }
       end
 
       context "with relative target" do
         let(:cask_token) { "generic-artifact-relative-target" }
-        it { is_expected.to fail_with(%r{target must be absolute path for generic artifact}) }
+        it { is_expected.to fail_with(/target must be absolute path for generic artifact/) }
       end
 
       context "with absolute target" do
         let(:cask_token) { "generic-artifact-absolute-target" }
-        it { should_not fail_with(%r{target required for generic artifact}) }
+        it { should_not fail_with(/target required for generic artifact/) }
       end
     end
 
@@ -260,7 +260,7 @@ describe Hbc::Audit do
 
         context "when doing the audit" do
           it "evaluates the block" do
-            expect(subject).to fail_with(%r{Boom})
+            expect(subject).to fail_with(/Boom/)
           end
         end
       end
@@ -276,12 +276,12 @@ describe Hbc::Audit do
 
       context "when cask token conflicts with a core formula" do
         let(:formula_names) { %w[with-binary other-formula] }
-        it { is_expected.to warn_with(%r{possible duplicate}) }
+        it { is_expected.to warn_with(/possible duplicate/) }
       end
 
       context "when cask token does not conflict with a core formula" do
         let(:formula_names) { %w[other-formula] }
-        it { should_not warn_with(%r{possible duplicate}) }
+        it { should_not warn_with(/possible duplicate/) }
       end
     end
 
@@ -298,7 +298,7 @@ describe Hbc::Audit do
           expect(verify).to receive(:all)
         end
 
-        it { should_not fail_with(%r{#{error_msg}}) }
+        it { should_not fail_with(/#{error_msg}/) }
       end
 
       context "when download fails" do
@@ -306,7 +306,7 @@ describe Hbc::Audit do
           expect(download).to receive(:perform).and_raise(StandardError.new(error_msg))
         end
 
-        it { is_expected.to fail_with(%r{#{error_msg}}) }
+        it { is_expected.to fail_with(/#{error_msg}/) }
       end
 
       context "when verification fails" do
@@ -315,7 +315,7 @@ describe Hbc::Audit do
           expect(verify).to receive(:all).and_raise(StandardError.new(error_msg))
         end
 
-        it { is_expected.to fail_with(%r{#{error_msg}}) }
+        it { is_expected.to fail_with(/#{error_msg}/) }
       end
     end
 
@@ -325,7 +325,7 @@ describe Hbc::Audit do
         expect(cask).to receive(:version).and_raise(StandardError.new)
       end
 
-      it { is_expected.to fail_with(%r{exception while auditing}) }
+      it { is_expected.to fail_with(/exception while auditing/) }
     end
   end
 end
diff --git a/Library/Homebrew/cask/spec/cask/cli/doctor_spec.rb b/Library/Homebrew/cask/spec/cask/cli/doctor_spec.rb
index b452fdb19f..38f8b50ac2 100644
--- a/Library/Homebrew/cask/spec/cask/cli/doctor_spec.rb
+++ b/Library/Homebrew/cask/spec/cask/cli/doctor_spec.rb
@@ -4,7 +4,7 @@ describe Hbc::CLI::Doctor do
   it "displays some nice info about the environment" do
     expect {
       Hbc::CLI::Doctor.run
-    }.to output(%r{\A==> macOS Release:}).to_stdout
+    }.to output(/\A==> macOS Release:/).to_stdout
   end
 
   it "raises an exception when arguments are given" do
diff --git a/Library/Homebrew/cask/spec/cask/system_command_spec.rb b/Library/Homebrew/cask/spec/cask/system_command_spec.rb
index 2af0958532..be70cb5e7e 100644
--- a/Library/Homebrew/cask/spec/cask/system_command_spec.rb
+++ b/Library/Homebrew/cask/spec/cask/system_command_spec.rb
@@ -84,7 +84,7 @@ describe Hbc::SystemCommand do
         (1..6).each do |i|
           expect {
             described_class.run(command, options)
-          }.to output(%r{==> #{ i }}).to_stdout
+          }.to output(/==> #{ i }/).to_stdout
         end
       end
 
diff --git a/Library/Homebrew/cask/test/cask/artifact/app_test.rb b/Library/Homebrew/cask/test/cask/artifact/app_test.rb
index 648146f9ab..acd5b2b633 100644
--- a/Library/Homebrew/cask/test/cask/artifact/app_test.rb
+++ b/Library/Homebrew/cask/test/cask/artifact/app_test.rb
@@ -243,7 +243,7 @@ describe Hbc::Artifact::App do
     describe "app is missing" do
       it "returns a warning and the supposed path to the app" do
         contents.size.must_equal 1
-        contents[0].must_match(%r{.*Missing App.*: #{target_path}})
+        contents[0].must_match(/.*Missing App.*: #{target_path}/)
       end
     end
   end
diff --git a/Library/Homebrew/cask/test/cask/cli/install_test.rb b/Library/Homebrew/cask/test/cask/cli/install_test.rb
index 57d7e0d7ee..c778d0d3c5 100644
--- a/Library/Homebrew/cask/test/cask/cli/install_test.rb
+++ b/Library/Homebrew/cask/test/cask/cli/install_test.rb
@@ -29,7 +29,7 @@ describe Hbc::CLI::Install do
 
     lambda {
       Hbc::CLI::Install.run("local-transmission", "")
-    }.must_output nil, %r{Warning: A Cask for local-transmission is already installed.}
+    }.must_output nil, /Warning: A Cask for local-transmission is already installed./
   end
 
   it "allows double install with --force" do
@@ -39,7 +39,7 @@ describe Hbc::CLI::Install do
 
     lambda {
       Hbc::CLI::Install.run("local-transmission", "--force")
-    }.must_output %r{==> Success! local-transmission was successfully installed!}
+    }.must_output(/==> Success! local-transmission was successfully installed!/)
   end
 
   it "skips dependencies with --skip-cask-deps" do
@@ -64,7 +64,7 @@ describe Hbc::CLI::Install do
       begin
         Hbc::CLI::Install.run("googlechrome")
       rescue Hbc::CaskError; end
-    }.must_output nil, %r{No available Cask for googlechrome\. Did you mean:\ngoogle-chrome}
+    }.must_output nil, /No available Cask for googlechrome\. Did you mean:\ngoogle-chrome/
   end
 
   it "returns multiple suggestions for a Cask fragment" do
@@ -72,7 +72,7 @@ describe Hbc::CLI::Install do
       begin
         Hbc::CLI::Install.run("google")
       rescue Hbc::CaskError; end
-    }.must_output nil, %r{No available Cask for google\. Did you mean one of:\ngoogle}
+    }.must_output nil, /No available Cask for google\. Did you mean one of:\ngoogle/
   end
 
   describe "when no Cask is specified" do
diff --git a/Library/Homebrew/cask/test/cask/cli/search_test.rb b/Library/Homebrew/cask/test/cask/cli/search_test.rb
index 4b15d8eab8..6eb6badb96 100644
--- a/Library/Homebrew/cask/test/cask/cli/search_test.rb
+++ b/Library/Homebrew/cask/test/cask/cli/search_test.rb
@@ -19,25 +19,25 @@ describe Hbc::CLI::Search do
 
   it "lists all available Casks with no search term" do
     out = capture_io { Hbc::CLI::Search.run }[0]
-    out.must_match(%r{google-chrome})
+    out.must_match(/google-chrome/)
     out.length.must_be :>, 1000
   end
 
   it "ignores hyphens in search terms" do
     out = capture_io { Hbc::CLI::Search.run("goo-gle-chrome") }[0]
-    out.must_match(%r{google-chrome})
+    out.must_match(/google-chrome/)
     out.length.must_be :<, 100
   end
 
   it "ignores hyphens in Cask tokens" do
     out = capture_io { Hbc::CLI::Search.run("googlechrome") }[0]
-    out.must_match(%r{google-chrome})
+    out.must_match(/google-chrome/)
     out.length.must_be :<, 100
   end
 
   it "accepts multiple arguments" do
     out = capture_io { Hbc::CLI::Search.run("google chrome") }[0]
-    out.must_match(%r{google-chrome})
+    out.must_match(/google-chrome/)
     out.length.must_be :<, 100
   end
 
@@ -49,11 +49,11 @@ describe Hbc::CLI::Search do
 
   it "Returns both exact and partial matches" do
     out = capture_io { Hbc::CLI::Search.run("mnemosyne") }[0]
-    out.must_match(%r{^==> Exact match\nmnemosyne\n==> Partial matches\nsubclassed-mnemosyne})
+    out.must_match(/^==> Exact match\nmnemosyne\n==> Partial matches\nsubclassed-mnemosyne/)
   end
 
   it "does not search the Tap name" do
     out = capture_io { Hbc::CLI::Search.run("caskroom") }[0]
-    out.must_match(%r{^No Cask found for "caskroom"\.\n})
+    out.must_match(/^No Cask found for "caskroom"\.\n/)
   end
 end
diff --git a/Library/Homebrew/cask/test/cask/cli/uninstall_test.rb b/Library/Homebrew/cask/test/cask/cli/uninstall_test.rb
index 6e0ea773bc..0368ad87ce 100644
--- a/Library/Homebrew/cask/test/cask/cli/uninstall_test.rb
+++ b/Library/Homebrew/cask/test/cask/cli/uninstall_test.rb
@@ -93,7 +93,7 @@ describe Hbc::CLI::Uninstall do
         Hbc::CLI::Uninstall.run("versioned-cask")
       end
 
-      out.must_match(%r{#{token} #{first_installed_version} is still installed.})
+      out.must_match(/#{token} #{first_installed_version} is still installed./)
       err.must_be :empty?
     end
   end
diff --git a/Library/Homebrew/cask/test/cask/dsl_test.rb b/Library/Homebrew/cask/test/cask/dsl_test.rb
index 4b3f88b1fc..d062875fac 100644
--- a/Library/Homebrew/cask/test/cask/dsl_test.rb
+++ b/Library/Homebrew/cask/test/cask/dsl_test.rb
@@ -250,7 +250,7 @@ describe Hbc::DSL do
   describe "appcast stanza" do
     it "allows appcasts to be specified" do
       cask = Hbc.load("with-appcast")
-      cask.appcast.to_s.must_match %r{^http}
+      cask.appcast.to_s.must_match(/^http/)
     end
 
     it "prevents defining multiple appcasts" do
@@ -270,12 +270,12 @@ describe Hbc::DSL do
   describe "gpg stanza" do
     it "allows gpg stanza to be specified" do
       cask = Hbc.load("with-gpg")
-      cask.gpg.to_s.must_match %r{\S}
+      cask.gpg.to_s.must_match(/\S/)
     end
 
     it "allows gpg stanza to be specified with :key_url" do
       cask = Hbc.load("with-gpg-key-url")
-      cask.gpg.to_s.must_match %r{\S}
+      cask.gpg.to_s.must_match(/\S/)
     end
 
     it "prevents specifying gpg stanza multiple times" do
diff --git a/Library/Homebrew/cask/test/cask/installer_test.rb b/Library/Homebrew/cask/test/cask/installer_test.rb
index 9253f40e76..f64ed8c176 100644
--- a/Library/Homebrew/cask/test/cask/installer_test.rb
+++ b/Library/Homebrew/cask/test/cask/installer_test.rb
@@ -239,7 +239,7 @@ describe Hbc::Installer do
       with_caveats = Hbc.load("with-caveats")
       lambda {
         Hbc::Installer.new(with_caveats).install
-      }.must_output %r{Here are some things you might want to know}
+      }.must_output(/Here are some things you might want to know/)
       with_caveats.must_be :installed?
     end
 
@@ -247,7 +247,7 @@ describe Hbc::Installer do
       with_installer_manual = Hbc.load("with-installer-manual")
       lambda {
         Hbc::Installer.new(with_installer_manual).install
-      }.must_output %r{To complete the installation of Cask with-installer-manual, you must also\nrun the installer at\n\n  '#{with_installer_manual.staged_path.join('Caffeine.app')}'}
+      }.must_output(/To complete the installation of Cask with-installer-manual, you must also\nrun the installer at\n\n  '#{with_installer_manual.staged_path.join('Caffeine.app')}'/)
       with_installer_manual.must_be :installed?
     end