GPL: meaning of "independent and separate works"

[Brian Kimball <bfk@footbag.org>]

(GPL, section 2):
> If identifiable sections of that work are not derived from the
> Program, and can be reasonably considered independent and separate
> works in themselves, then this License, and its terms, do not apply to
> those sections when you distribute them as separate works.

Does US copyright law provide special legal definitions of 'independent'
and 'separate' or are these used in the technical sense of the words?

In other words, suppose I a) add a special switch to GNU's 'cp' that no
other 'cp' has, b) write a shell script that calls this 'cp' and uses
that switch, and then c) distribute the modified version of 'cp' and the
script together.  Then my script would, technically speaking, be
dependent on the 'cp' that I distributed, which is GPLed.  So if
'independent' is used in the technical sense then my script would need
to be GPLed, I assume, even though it is solely my own work and is not a
derivate work of any GPLed program.

-- 
Brian Kimball