Is there some reason you have not provided any details about your system or what the problem is that you think running SFC or Comboxfix is going to resolve - or are you just practicing?
You must have at least one space between command prompt program arguments and you can't have "too many".
50 spaces will work as well as one space:
Sometimes when you see suggestions to run commands it is not clear that at lest one space is needed between the arguments so if I were to suggest such a thing I would try to make it clear by showing the command with more than one space:
Illustrating like that reduces the chances of the next message being "It didn't work" or "I get an error message", etc.
Edited by joseibarra, 03 November 2017 - 01:59 AM.