Clon separates the command-line in two parts. The left part contains
option calls and packs while the right part contains the rest. The right
part is also called the postfix).
You can force this distinction by using the special construct ‘--’
on the command-line. Everything that follows it will be completely ignored
by Clon (not necessarily by the application itself though).
In the case you don’t split your command-line explicitly, Clon does
this for you automatically by noticing where the last option (or its
potential argument) stands. The behavior is different from that of
explicit splitting in one regard however: if the application is not
expecting any postfix and there’s an implicit one, then Clon will
throw an error at your face.
One final note on command-line separation: in the case an application’s
postfix is supposed to contain something looking like an option (perhaps
real options to pass on to another program), you need an
explicit separator. Otherwise, Clon will be confused: it could for
instance wrongly detect unknown options, junk on the command-line etc.
You don’t want to confuse Clon. Clon is nasty when it is scared.