              self.fix_manifest()
              files = self.config.bundle.get_files()
  
-@@ -272,6 +273,7 @@ def cmd_dev(config, args):
+@@ -258,8 +259,9 @@ def cmd_dev(config, args):
+     '''Setup for development'''
+ 
+     if args:
++        print 'ERROR - Wrong argument.'
+         print 'Usage: %prog dev'
+-        return
++        exit (1)
+ 
+     bundle_path = env.get_user_activities_path()
+     if not os.path.isdir(bundle_path):
+@@ -272,13 +274,15 @@ def cmd_dev(config, args):
              print 'ERROR - The bundle has been already setup for development.'
          else:
              print 'ERROR - A bundle with the same name is already installed.'

 
 def cmd_release(config, args):
     '''Do a new release of the bundle'''
@@ -364,12 +367,12 @@ def cmd_release(config, args):
 
     if not os.path.isdir('.git'):
         print 'ERROR - this command works only for git repositories'

 
     print 'Done.'
 
@@ -463,8 +473,9 @@ def cmd_build(config, args):
     '''Build generated files'''
 
     if args:
+        print 'ERROR - Wrong argument.'
         print 'Usage: %prog build'
-        return
+        exit (1)
 
     builder = Builder(config)
     builder.build()
@@ -492,7 +503,9 @@ def start(bundle_name=None):
     try:
         globals()['cmd_' + args[0]](config, args[1:])
     except (KeyError, IndexError):
+        print 'ERROR - Wrong command or argument.'
         print_commands()
+        exit (1)
 
