Index: Lib/pdb.py
===================================================================
--- Lib/pdb.py	(revision 78430)
+++ Lib/pdb.py	(working copy)
@@ -279,10 +279,12 @@
     def handle_command_def(self,line):
         """ Handles one command line during command list definition. """
         cmd, arg, line = self.parseline(line)
+        if not cmd:
+            return
         if cmd == 'silent':
             self.commands_silent[self.commands_bnum] = True
             return # continue to handle other cmd def in the cmd list
-        elif cmd == 'end':
+        if cmd == 'end':
             self.cmdqueue = []
             return 1 # end of cmd list
         cmdlist = self.commands[self.commands_bnum]