diff --git a/cccli/command/command.py b/cccli/command/command.py
index ca810bcbf0300bc78f62fe3b0a4055f66855e6b4..1b40c26e2b28baa01e38b72dc8f49846b2101787 100644
--- a/cccli/command/command.py
+++ b/cccli/command/command.py
@@ -43,6 +43,7 @@ class OptionCommand(Command):
     def __init__(self, cli, argv0):
         Command.__init__(self, cli, argv0)
         self.optionparser = OptionCommand.OptionCommandParser(prog=argv0)
+        self.set_usage("%prog [options]")
         self.options = None
         self.args = list()
 
diff --git a/cccli/command/shell.py b/cccli/command/shell.py
index 7fc55490ba4d4c08d58d6e93782a33723a115820..19c48cae98c44bd1b05492d26340f1d52c81b7e3 100644
--- a/cccli/command/shell.py
+++ b/cccli/command/shell.py
@@ -29,6 +29,8 @@ class Command_version(Command):
 class Command_history(Command):
     '''Show commands history'''
     def __call__(self, argv):
+        if len(argv) != 1:
+            raise cmdBadArgument()
         if not self.printer.history:
             raise cmdError("not available")
         for l in self.printer.history:
@@ -39,6 +41,8 @@ class Command_clear(Command):
     '''Clear tty'''
 
     def __call__(self, argv):
+        if len(argv) != 1:
+            raise cmdBadArgument()
         self.printer.out("\033[H\033[2J", nl="")