On Sun 07 Oct 2018 at 08:32:42 (-0500), Richard Owlett wrote:
All my machines have use Stretch DVD1 for installation.
I have a low monthly data cap - currently at my limit.
One machine has an apt-get update and upgrade with the addition of
some packages not on DVD1.
I've not intentionally deleted any cached files.
Is it possible to use the cached data on another machine?
Yes, every different .deb file has a unique name so you can copy them
wholesale onto a stick and use them over and over, and add more to
your collection at any time.
What should I be reading?
Copying them from archives/ to a stick really needs no documentation
beyond avoiding overwriting previous copies with -n, not because it
would cause a problem but just that it wastes time.
If you're impatient and want to copy files to the stick during
installation, note that (last time I looked) cp has no -n switch
at this time.
If you want to minimise traffic to the max, then you can copy the
files from the stick to the installation as soon as the directory
becomes available. IIRC that's at the point you are about to select
"Install the base system". So a sequence of commands on VC2 would be:
# cd /target/var/cache/apt/archives/
if that fails, than just go one more step on VC1 and try again.
# mount -t auto /dev/sdz9 /mnt
where z9 is whatever is appropriate.
# cp -ip /mnt/whatever/*deb /target/var/cache/apt/archives/
assuming the files on the stick are all are in directory "whatever".
(Why bother? Because you'll run out of top-level entries if the
stick is VFAT and you write all the files at top level.)
# umount /mnt