-a
Output all.
-c arg
Output just arg.
--long
Output all day long.
/V
A VMS/DOS-style option.
-p
This option has two paragraphs in the description. This is the first.
This is the second. Blank lines may be omitted between options (as above) or left in (as here and below).
--very-long-option
A VMS-style option. Note the adjustment for the required two spaces.
--an-even-longer-option
The description can also start on the next line.
-2, --two
This option has two variants.
-f FILE, --file=FILE
These two options are synonyms; both have arguments.
-f <[path]file>
Option argument placeholders must start with a letter or be wrapped in angle brackets.
-d <src dest>
Angle brackets are also required if an option expects more than one argument.