gistfile1.txt

failbowl:~(master) $ irb
>> X = 1
=> 1
>> undef_const :X
NoMethodError: undefined method `undef_const' for main:Object
  from (irb):2
>> const_undef :X
NoMethodError: undefined method `const_undef' for main:Object
	from (irb):3
>> const_delete :X
NoMethodError: undefined method `const_delete' for main:Object
	from (irb):4
>> delete_const :X
NoMethodError: undefined method `delete_const' for main:Object
	from (irb):5
>> undef :X
NameError: undefined method `X' for class `Object'
	from (irb):6
>> ^D
failbowl:~(master) $ python
Python 2.7.1 (r271:86832, Jul 31 2011, 19:30:53) 
[GCC 4.2.1 (Based on Apple Inc. build 5658) (LLVM build 2335.15.00)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> X = 1
>>> del X
>>> ^D