[conspire] Install openscad. WAS: Re: upgrade and grub

[Rick Moen]

Quoting Paul Zander (paulz at ieee.org):

> Before I go off half-cocked, here is what I think I should do. 
> Basically manually download 3 specific files and then run dpkg.

Just a word of context:  Deirdre and I are at a convention in Denver,
and I really can't devote huge amounts of time to this.  The good news:
If you try to do 'dpkg -i $PACKAGE1 $PACKAGE2 $PACKAGE3 [...]' and the
requested action cannot be done because some dependency isn't being
satisfied, dpkg will halt, tell you the problem, and not do anything
(else).

At which point, you say 'Ah, I see, I got the wrong version deb of
libfoo', fix that, and try again.

You'll note that this is a somewhat annoying and checking-intensive
process, which will doubtless remind you of how nice apt-get's automatic
dependency resolution is.  Unfortunately, because you are seeking to
install a package no longer in your development track's
(Debian-testing's) package collection, there's no obvious way to do what
you want using normal apt-based package operations, so you're obliged to 
collect the needed pieces manually, doing yourself the work that apt-get
normally would.

Don't be surprised to get the mix of packages wrong a time or two.

> I don't need debug, and I probably should get latest entry, so
> download the last file.

Wrong criterion.  You should get whatever satisfies the dependencies
for the openscad package that makes it necessary.  (No, you don't
need a debug version.)  What versions are required?  Short of pulling
the openscad deb apart to look at the metadata (do-able, but a bit of
work), the easiest way is to just try to install using dpkg, get the
combination of app package and libs packages wrong the first time, and 
fix it by heeding dpkg's complaint about why that operation won't work.

I warned that this is going to take a bit of work.  That's exactly the
part where you have to do some work.

> Now the 3 files are in a known directory. 
> Can any directory be used?  

Sure.  I tend to use /tmp/ .

But, when I say 'any directory'...:

> Some web searching suggests /var/cache/apt/archives/
> Is this necessary, or just a common practice?

The apt tools place a copy of any installed package into
there.  You would normally leave the directory alone.   If
hypothetically you wanted to reclaim some disk space, you could do
'apt-get clean' to prune the contents of /var/cache/apt/archives/ and
/var/cache/apt/archives/partial/ (removing everything but lock files).

Be careful about advice from dodgy characters on the Internet (including
me).

> Finally: `apt-get update`
> `dpkg -i <local_path>openscad`

Personally, I would marshall into a convenient place (such as /tmp/) all
of the deb files I think I need -- after making sure that I am meeting 
dependency requirements -- and then install them all using a single
'dpkg -i' operation.  But suit yourself.  There's nothing particularly
harmful about, say, putting in using dpkg an ultimately undesirable
version of a libs package, but then, after you figure out it's not what
you wanted, you'd end up wanting to remove it, so why not just assemble
all the pieces needed and put them in all at once?