Use guard clauses.

Library/Homebrew/cask/lib/hbc/cli/search.rb

@@ -41,7 +41,9 @@ module Hbc
           ohai "Exact match"
           puts exact_match
         end
-        unless partial_matches.empty?
+
+        return if partial_matches.empty?
+
         if extract_regexp search_term
           ohai "Regexp matches"
         else
@@ -49,7 +51,6 @@ module Hbc
         end
         puts Formatter.columns(partial_matches)
       end
-      end
 
       def self.help
         "searches all known Casks"

Library/Homebrew/cask/lib/hbc/installer.rb

@@ -28,7 +28,8 @@ module Hbc
 
     def self.print_caveats(cask)
       odebug "Printing caveats"
-      unless cask.caveats.empty?
+      return if cask.caveats.empty?
+
       output = capture_output do
         cask.caveats.each do |caveat|
           if caveat.respond_to?(:eval_and_print)
@@ -39,12 +40,10 @@ module Hbc
         end
       end
 
-        unless output.empty?
+      return if output.empty?
       ohai "Caveats"
       puts output
     end
-      end
-    end
 
     def self.capture_output(&block)
       old_stdout = $stdout

Library/Homebrew/cask/lib/hbc/utils.rb

@@ -137,14 +137,14 @@ module Hbc
 
     def self.nowstamp_metadata_path(container_path)
       @timenow ||= Time.now.gmtime
-      if container_path.respond_to?(:join)
+      return unless container_path.respond_to?(:join)
+
       precision = 3
       timestamp = @timenow.strftime("%Y%m%d%H%M%S")
       fraction = format("%.#{precision}f", @timenow.to_f - @timenow.to_i)[1..-1]
       timestamp.concat(fraction)
       container_path.join(timestamp)
     end
-    end
 
     def self.size_in_bytes(files)
       Array(files).reduce(0) { |a, e| a + (File.size?(e) || 0) }

Library/Homebrew/cleanup.rb

@@ -10,11 +10,10 @@ module Homebrew
       cleanup_cellar
       cleanup_cache
       cleanup_logs
-      unless ARGV.dry_run?
+      return if ARGV.dry_run?
       cleanup_lockfiles
       rm_ds_store
     end
-    end
 
     def self.update_disk_cleanup_size(path_size)
       @disk_cleanup_size += path_size

Library/Homebrew/descriptions.rb

@@ -57,7 +57,8 @@ class Descriptions
   # If it does exist, but the Report is empty, just touch the cache file.
   # Otherwise, use the report to update the cache.
   def self.update_cache(report)
-    if CACHE_FILE.exist?
+    return unless CACHE_FILE.exist?
+
     if report.empty?
       FileUtils.touch CACHE_FILE
     else
@@ -69,12 +70,12 @@ class Descriptions
                             renamings.map(&:first))
     end
   end
-  end
 
   # Given an array of formula names, add them and their descriptions to the
   # cache. Save the updated cache to disk, unless explicitly told not to.
   def self.cache_formulae(formula_names, options = { save: true })
-    if cache
+    return unless cache
+
     formula_names.each do |name|
       begin
         desc = Formulary.factory(name).desc
@@ -84,16 +85,14 @@ class Descriptions
     end
     save_cache if options[:save]
   end
-  end
 
   # Given an array of formula names, remove them and their descriptions from
   # the cache. Save the updated cache to disk, unless explicitly told not to.
   def self.uncache_formulae(formula_names, options = { save: true })
-    if cache
+    return unless cache
     formula_names.each { |name| @cache.delete(name) }
     save_cache if options[:save]
   end
-  end
 
   # Given a regex, find all formulae whose specified fields contain a match.
   def self.search(regex, field = :either)

Library/Homebrew/extend/ENV/std.rb

@@ -11,10 +11,9 @@ module Stdenv
   DEFAULT_FLAGS = "-march=core2 -msse4".freeze
 
   def self.extended(base)
-    unless ORIGINAL_PATHS.include? HOMEBREW_PREFIX/"bin"
+    return if ORIGINAL_PATHS.include? HOMEBREW_PREFIX/"bin"
     base.prepend_path "PATH", "#{HOMEBREW_PREFIX}/bin"
   end
-  end
 
   # @private
   def setup_build_environment(formula = nil)

Library/Homebrew/sandbox.rb

@@ -27,11 +27,10 @@ class Sandbox
   end
 
   def self.print_sandbox_message
-    unless @printed_sandbox_message
+    return if @printed_sandbox_message
     ohai "Using the sandbox"
     @printed_sandbox_message = true
   end
-  end
 
   def initialize
     @profile = SandboxProfile.new