I've gotten through one user's guide that was useless. I've found a rather good one that I can understand.
As an exercise of the book I'm going thru man pages and I'm in "find" this is part of the man explanation :find -size [[+|-]]<size>
I understand that <> anything there is replaced with what is needed to operate, also that the square brackets normally do the same however they have brackets inside brackets? I think I understand the + and - what they are looking for but why the "pipe"?