diff --git a/lib/core_ext/hash_with_indifferent_access.rb b/lib/core_ext/hash_with_indifferent_access.rb
new file mode 100644
index 0000000..cfb83e7
--- /dev/null
+++ b/lib/core_ext/hash_with_indifferent_access.rb
@@ -0,0 +1,9 @@
+class Thor
+  module CoreExt #:nodoc:
+    class HashWithIndifferentAccess < ::Hash #:nodoc:
+      def has_key?(key)
+        super(convert_key(key))
+      end
+    end
+  end
+end
diff --git a/lib/guard.rb b/lib/guard.rb
index 8923320..607e759 100644
--- a/lib/guard.rb
+++ b/lib/guard.rb
@@ -1,3 +1,5 @@
+require 'core_ext/hash_with_indifferent_access'
+
 module Guard
 
   autoload :UI,           'guard/ui'
diff --git a/lib/guard/cli.rb b/lib/guard/cli.rb
index 9bf323a..98c4fc8 100644
--- a/lib/guard/cli.rb
+++ b/lib/guard/cli.rb
@@ -10,6 +10,8 @@ module Guard
     method_option :debug,  :type => :boolean, :default => false, :aliases => '-d', :banner => "Print debug messages"
     method_option :group,  :type => :array,   :default => [],    :aliases => '-g', :banner => "Run only the passed groups"
 
+    method_option :guardfile, :type => :string,  :default => './Guardfile', :aliases => '-C', :banner => "Specify a Guardfile"
+
     desc "start", "Starts Guard"
     def start
       ::Guard.start(options)