Use guard clauses.

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

@@ -41,14 +41,15 @@ module Hbc
           ohai "Exact match"
           puts exact_match
         end
-        unless partial_matches.empty?
-          if extract_regexp search_term
-            ohai "Regexp matches"
-          else
-            ohai "Partial matches"
-          end
-          puts Formatter.columns(partial_matches)
+
+        return if partial_matches.empty?
+
+        if extract_regexp search_term
+          ohai "Regexp matches"
+        else
+          ohai "Partial matches"
         end
+        puts Formatter.columns(partial_matches)
       end
 
       def self.help

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

@@ -28,22 +28,21 @@ module Hbc
 
     def self.print_caveats(cask)
       odebug "Printing caveats"
-      unless cask.caveats.empty?
-        output = capture_output do
-          cask.caveats.each do |caveat|
-            if caveat.respond_to?(:eval_and_print)
-              caveat.eval_and_print(cask)
-            else
-              puts caveat
-            end
+      return if cask.caveats.empty?
+
+      output = capture_output do
+        cask.caveats.each do |caveat|
+          if caveat.respond_to?(:eval_and_print)
+            caveat.eval_and_print(cask)
+          else
+            puts caveat
           end
         end
-
-        unless output.empty?
-          ohai "Caveats"
-          puts output
-        end
       end
+
+      return if output.empty?
+      ohai "Caveats"
+      puts output
     end
 
     def self.capture_output(&block)

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

@@ -137,13 +137,13 @@ module Hbc
 
     def self.nowstamp_metadata_path(container_path)
       @timenow ||= Time.now.gmtime
-      if 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
+      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
 
     def self.size_in_bytes(files)

Library/Homebrew/cleanup.rb

@@ -10,10 +10,9 @@ module Homebrew
       cleanup_cellar
       cleanup_cache
       cleanup_logs
-      unless ARGV.dry_run?
-        cleanup_lockfiles
-        rm_ds_store
-      end
+      return if ARGV.dry_run?
+      cleanup_lockfiles
+      rm_ds_store
     end
 
     def self.update_disk_cleanup_size(path_size)

Library/Homebrew/descriptions.rb

@@ -57,42 +57,41 @@ 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?
-      if report.empty?
-        FileUtils.touch CACHE_FILE
-      else
-        renamings = report.select_formula(:R)
-        alterations = report.select_formula(:A) + report.select_formula(:M) +
-                      renamings.map(&:last)
-        cache_formulae(alterations, save: false)
-        uncache_formulae(report.select_formula(:D) +
-                              renamings.map(&:first))
-      end
+    return unless CACHE_FILE.exist?
+
+    if report.empty?
+      FileUtils.touch CACHE_FILE
+    else
+      renamings = report.select_formula(:R)
+      alterations = report.select_formula(:A) + report.select_formula(:M) +
+                    renamings.map(&:last)
+      cache_formulae(alterations, save: false)
+      uncache_formulae(report.select_formula(:D) +
+                            renamings.map(&:first))
     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
-      formula_names.each do |name|
-        begin
-          desc = Formulary.factory(name).desc
-        rescue FormulaUnavailableError, *FormulaVersions::IGNORED_EXCEPTIONS
-        end
-        @cache[name] = desc
+    return unless cache
+
+    formula_names.each do |name|
+      begin
+        desc = Formulary.factory(name).desc
+      rescue FormulaUnavailableError, *FormulaVersions::IGNORED_EXCEPTIONS
       end
-      save_cache if options[:save]
+      @cache[name] = desc
     end
+    save_cache if options[:save]
   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
-      formula_names.each { |name| @cache.delete(name) }
-      save_cache if options[:save]
-    end
+    return unless cache
+    formula_names.each { |name| @cache.delete(name) }
+    save_cache if options[:save]
   end
 
   # Given a regex, find all formulae whose specified fields contain a match.

Library/Homebrew/extend/ENV/std.rb

@@ -11,9 +11,8 @@ module Stdenv
   DEFAULT_FLAGS = "-march=core2 -msse4".freeze
 
   def self.extended(base)
-    unless ORIGINAL_PATHS.include? HOMEBREW_PREFIX/"bin"
-      base.prepend_path "PATH", "#{HOMEBREW_PREFIX}/bin"
-    end
+    return if ORIGINAL_PATHS.include? HOMEBREW_PREFIX/"bin"
+    base.prepend_path "PATH", "#{HOMEBREW_PREFIX}/bin"
   end
 
   # @private

Library/Homebrew/sandbox.rb

@@ -27,10 +27,9 @@ class Sandbox
   end
 
   def self.print_sandbox_message
-    unless @printed_sandbox_message
-      ohai "Using the sandbox"
-      @printed_sandbox_message = true
-    end
+    return if @printed_sandbox_message
+    ohai "Using the sandbox"
+    @printed_sandbox_message = true
   end
 
   def initialize