--- a/cwconfig.py	Fri Jun 26 13:04:25 2015 +0200
+++ b/cwconfig.py	Thu Jun 25 22:12:49 2015 +0200
@@ -835,7 +835,7 @@
 
     # set by upgrade command
     verbosity = 0
-
+    cmdline_options = None
     options = CubicWebNoAppConfiguration.options + (
         ('log-file',
          {'type' : 'string',
@@ -1029,7 +1029,7 @@
         # or site_cubicweb files
         self.load_file_configuration(self.main_config_file())
         # configuration initialization hook
-        self.load_configuration()
+        self.load_configuration(**(self.cmdline_options or {}))
 
     def add_cubes(self, cubes):
         """add given cubes to the list of used cubes"""
@@ -1096,9 +1096,9 @@
         infos.append('cubicweb-%s' % str(self.cubicweb_version()))
         return md5(';'.join(infos)).hexdigest()
 
-    def load_configuration(self):
+    def load_configuration(self, **kw):
         """load instance's configuration files"""
-        super(CubicWebConfiguration, self).load_configuration()
+        super(CubicWebConfiguration, self).load_configuration(**kw)
         if self.apphome and not self.creating:
             # init gettext
             self._gettext_init()

--- a/cwctl.py	Fri Jun 26 13:04:25 2015 +0200
+++ b/cwctl.py	Thu Jun 25 22:12:49 2015 +0200
@@ -520,7 +520,12 @@
           'default': None, 'choices': ('debug', 'info', 'warning', 'error'),
           'help': 'debug if -D is set, error otherwise',
           }),
-        )
+        ('param',
+         {'short': 'p', 'type' : 'named', 'metavar' : 'key1:value1,key2:value2',
+          'default': {},
+          'help': 'override <key> configuration file option with <value>.',
+         }),
+       )
 
     def start_instance(self, appid):
         """start the instance's server"""
@@ -534,6 +539,8 @@
                 "- '{ctl} pyramid {appid}' (requires the pyramid cube)\n")
             raise ExecutionError(msg.format(ctl='cubicweb-ctl', appid=appid))
         config = cwcfg.config_for(appid, debugmode=self['debug'])
+        # override config file values with cmdline options
+        config.cmdline_options = self.config.param
         init_cmdline_log_threshold(config, self['loglevel'])
         if self['profile']:
             config.global_set_option('profile', self.config.profile)

--- a/devtools/__init__.py	Fri Jun 26 13:04:25 2015 +0200
+++ b/devtools/__init__.py	Thu Jun 25 22:12:49 2015 +0200
@@ -173,8 +173,8 @@
         return self._apphome
     appdatahome = apphome
 
-    def load_configuration(self):
-        super(TestServerConfiguration, self).load_configuration()
+    def load_configuration(self, **kw):
+        super(TestServerConfiguration, self).load_configuration(**kw)
         # no undo support in tests
         self.global_set_option('undo-enabled', 'n')
 

--- a/devtools/devctl.py	Fri Jun 26 13:04:25 2015 +0200
+++ b/devtools/devctl.py	Thu Jun 25 22:12:49 2015 +0200
@@ -73,7 +73,7 @@
         return None
     def init_log(self):
         pass
-    def load_configuration(self):
+    def load_configuration(self, **kw):
         pass
     def default_log_file(self):
         return None

--- a/web/webconfig.py	Fri Jun 26 13:04:25 2015 +0200
+++ b/web/webconfig.py	Thu Jun 25 22:12:49 2015 +0200
@@ -375,9 +375,9 @@
             if exists(fpath):
                 yield join(fpath)
 
-    def load_configuration(self):
+    def load_configuration(self, **kw):
         """load instance's configuration files"""
-        super(WebConfiguration, self).load_configuration()
+        super(WebConfiguration, self).load_configuration(**kw)
         # load external resources definition
         self._init_base_url()
         self._build_ui_properties()