[ubuntu-uk] value of /var/cache/apt/archives ?

[alan c]

David Pashley wrote:
> On Dec 19, 2006 at 12:21, alan c praised the llamas by saying:
>> I have just discovered that /var/cache/apt/archives seems to contain 
>> all the installed updates  since original install. Is this a correct 
>> belief please?
>> 
>> I do not want to clear this, not just now, anyway - I am very 
>> interested in using this archive to create a CD from time to time in 
>> order to allow me to install and update PCs of several friends who 
>> have only a very slow dialup internet connection. If I can do this it 
>> will be important for me (and them).
> 
> Check out apt-move, apt-zip and debmirror which may provide you with
> some suitable tools to make your job easier.
> 
> Once you have all your files you want, you might be interested in
> apt-get autoclean and apt-get clean. Check the man page to see what they
> do and the difference between them.

I am still rather failing at an early hurdle unfortunately.
I am working on the thought that the files I need are already in
/var/cache/apt/archives
and after burning these to CDR I have tried to then use
sudo apt-get -o update dir::cache=/media/cdrom0/apt/archives
and I get a response:
E: Option update: Configuration item specification must have an =<val>.

any thoughts?
tia
-- 
alan cocks
Kubuntu user#10391