-help command displays a terse reminder of the command-line options:
The help output uses the following symbolic conventions:
<>— items between angle brackets indicate information that you must provide.
()— items within parentheses indicate options that are treated as a group in the help command output.
ALL_CAPS— items spelled out in capital letters indicate a set of options that is described separately.
OR. For example, ( A | B ), means item A or item B.
?— 0 or 1. A question mark following an item indicates that an item is optional and that only one instance can occur, if used.
*— 0 or more. An asterisk following an item indicates that an item is optional and that any number of instances can occur.
+— 1 or more. A plus sign following an item indicates that an item is required and that multiple instances can occur.
no symbol — If an item has no suffix symbol, then that item is required and only one instance can occur.