Hi Damin,

Thanks for your help, however, as I said I am completely new and don't seem to be able to make it work.
I have saved the text wrangler file on my desktop, so I open the terminal, type irb for ruby,
and on the next line write /Desktop/calc.rb and I get an error, here the full deal:

Last login: Sat Nov 10 15:20:19 on ttys000
iMac-de-Carlos:~ carlosamengual$ irb
>> /Desktop/calc.rb
SyntaxError: compile error
(irb):1: unknown regexp options - calc
  from (irb):1
>>
Any help would be greatly appreciated!!