--- a/piecrust/main.py	Tue Mar 01 22:27:04 2016 -0800
+++ b/piecrust/main.py	Tue Mar 01 22:27:28 2016 -0800
@@ -40,7 +40,8 @@
 
 
 class NullPieCrust:
-    def __init__(self):
+    def __init__(self, theme_site=False):
+        self.theme_site = theme_site
         self.root_dir = None
         self.debug = False
         self.templates_dirs = []
@@ -50,6 +51,9 @@
         self.plugin_loader = PluginLoader(self)
         self.env = None
 
+    def useSubCache(self, cache_name, cache_key):
+        pass
+
 
 def main():
     if sys.platform == 'darwin':
@@ -84,6 +88,10 @@
             '--root',
             help="The root directory of the website.")
     parser.add_argument(
+            '--theme',
+            action='store_true',
+            help="Makes the current command apply to a theme website.")
+    parser.add_argument(
             '--config',
             dest='config_variant',
             help="The configuration variant to use for this command.")
@@ -196,15 +204,19 @@
         root = os.path.expanduser(pre_args.root)
     else:
         try:
-            root = find_app_root()
+            root = find_app_root(theme=pre_args.theme)
         except SiteNotFoundError:
             root = None
 
     if not root:
-        app = NullPieCrust()
+        app = NullPieCrust(
+                theme_site=pre_args.theme)
     else:
-        app = PieCrust(root, cache=(not pre_args.no_cache),
-                       debug=pre_args.debug)
+        app = PieCrust(
+                root,
+                theme_site=pre_args.theme,
+                cache=(not pre_args.no_cache),
+                debug=pre_args.debug)
 
     # Build a hash for a custom cache directory.
     cache_key = 'default'