NESTING

It looks complicated: brackets or braces inside more brackets or braces
is called "nesting", but it's not really so difficult.

                     THE RULES ARE BASICALLY SIMPLE

Is it a variable or a KEYWORD?  Is it inside or outside a [ ] or a { }?
Is the punctuation that goes with it inside or outside the [ ] or { }?

[A[,B]]   NESTED             A and B are parameters of some command. ,B
            BRACKETS         nests inside A.  A is optional--use it if
                             you want.  Use A and you can also use ,B.
                             If you don't use A, you can't use ,B.

[A]       STACKED            A, B, and C are all optional parameters of
[B]         BRACKETS         the command.  You can choose NONE of them
[C]                          or ONE of them -- but NO MORE than one.
{A}       STACKED            A, B, and C are parameters of the command.
{B}         BRACES           The braces tell you that you MUST pick and
{C}                          use one...but ONLY ONE.
                                                ...Please press NEXT