diff --git a/Library/Homebrew/cli/parser.rb b/Library/Homebrew/cli/parser.rb
index f54633f9ea..75ff6ed78c 100644
--- a/Library/Homebrew/cli/parser.rb
+++ b/Library/Homebrew/cli/parser.rb
@@ -539,7 +539,7 @@ module Homebrew
 
       def process_option(*args)
         option, = @parser.make_switch(args)
-        @processed_options.reject! { |existing| option.long.first.present? && existing.second == option.long.first }
+        @processed_options.reject! { |existing| existing.second == option.long.first } if option.long.first.present?
         @processed_options << [option.short.first, option.long.first, option.arg, option.desc.first]
       end
 
diff --git a/Library/Homebrew/cmd/options.rb b/Library/Homebrew/cmd/options.rb
index 29a7038e34..ba6616c400 100644
--- a/Library/Homebrew/cmd/options.rb
+++ b/Library/Homebrew/cmd/options.rb
@@ -39,8 +39,10 @@ module Homebrew
       puts_options Formula.to_a.sort, args: args
     elsif args.installed?
       puts_options Formula.installed.sort, args: args
-    elsif !args.command.nil?
+    elsif args.command.present?
       cmd_options = Commands.command_options(args.command)
+      odie "Unknown command: #{args.command}" if cmd_options.nil?
+
       if args.compact?
         puts cmd_options.sort.map(&:first) * " "
       else
diff --git a/Library/Homebrew/commands.rb b/Library/Homebrew/commands.rb
index 62a5e84e57..1f7676178a 100644
--- a/Library/Homebrew/commands.rb
+++ b/Library/Homebrew/commands.rb
@@ -197,7 +197,7 @@ module Commands
     HOMEBREW_CACHE.mkpath
 
     cmds = commands(aliases: true).reject do |cmd|
-      # TODO: remove the cask check when `brew cask` is removed
+      # TODO: (2.8) remove the cask check when `brew cask` is removed
       cmd.start_with?("cask ") || Homebrew::Completions::COMPLETIONS_EXCLUSION_LIST.include?(cmd)
     end
 
@@ -206,8 +206,8 @@ module Commands
   end
 
   def command_options(command)
-    path = Commands.path(command)
-    return unless path
+    path = self.path(command)
+    return if path.blank?
 
     if cmd_parser = Homebrew::CLI::Parser.from_cmd_path(path)
       cmd_parser.processed_options.map do |short, long, _, desc|
@@ -229,8 +229,8 @@ module Commands
   end
 
   def named_args_type(command)
-    path = Commands.path(command)
-    return unless path
+    path = self.path(command)
+    return if path.blank?
 
     cmd_parser = Homebrew::CLI::Parser.from_cmd_path(path)
     return if cmd_parser.blank?