Fixed most input validation bugs, and did too many improvements to remember. Did I mention that I am typing these words with my hands?

shell.py

@@ -133,7 +133,10 @@ class Shell(object):
         self.__exit = False
             
     def man(self, args):
-        help(self.__commands[args[0]])
+        if (len(args)):
+            help(self.__commands[args[0]])
+        else:
+            print("Usage: help <commamd>\nCommands:\n\t{}".format('\n\t'.join(list(self.__commands.keys()))))
                 
     def registerCommand(self, commandName: str, command: _types.FunctionType):
         """command must be a function that takes one argument: a list of strings,
@@ -288,10 +291,10 @@ $>=0 - $>=n is the nth and later arguments"""
         else:
             self.handleUnknownCommand(command)
         
-    def handleUnknownCommand(self, command):
+    def handleUnknownCommand(self, command: list):
         """Handle commands that aren't registered. Override this if you want to do
 something with those commands."""
-        print("Bad command.")
+        print(f"Unknown command: {' '.join(command)}")
         
     def update(self):
         """Runs at the end of each loop. Does nothing by default. Override this if