[vox-tech] Debian Unstable - apt strangeness

[Peter Jay Salzman]

On Fri 13 Aug 04,  3:29 PM, Rick Moen <rick at linuxmafia.com> said:
> Quoting Peter Jay Salzman (p at dirac.org):
> 
> > For example:
> > 
> > Dpkg doesn't believe this package exists:
> > 
> >    lucifer# dpkg -l libgimp2.0
> >    No packages found matching libgimp2.0.
> 
> I think you're misinterpreting:  dpkg is merely saying that no package
> matching that ASCII pattern is _installed_.  dpkg knows nothing about 
> available packages (as indicated in /var/lib/apt/lists/*Packages and
> /var/lib/dpkg/available).  It knows only about the contents of
> /var/lib/dpkg/status -- the "installed packages" database.

I'm not sure this is right.   I've always used "dpkg -l" to list
packages, whether installed or not.  Whether previously installed (and
then removed) or not.

For example, there's a package called 9wm.  I don't know what it is, and
I'm fairly sure it has never been installed on any of my systems.  On my
workstation:

   p at satan$ dpkg -l 9wm
   pn  9wm            <none>         (no description available)

On my game machine:

   p at lucifer$ dpkg -l 9wm
   No packages found matching 9wm.

In fact, on satan, I can even do a "dpkg -p" on that package (turns out
to be a window manager that emulates the "Plan 9" desktop, whatever that
is!).  On lucifer, as you'd expect, I can't get a -p listing for 9wm.


> > In fact, dpkg is pretty much clueless about gimp in general:
> > 
> >    lucifer# dpkg -l "*gimp*"
> >    ||/ Name           Version        Description
> >    +++-==============-==============-==========================
> >    un  gimp1.3        <none>         (no description available)
> 
> I'm pretty sure that "un" means "Desired=Unknown, Status=Not installed"
> (i.e., that the u and the n are separate key values with those meanings).
> But I could be wrong.
 
I'm pretty clueless about that.  I've looked it up before, but it's
confusing because I have "desired == purge" status for packages that
were never installed on my system.  I think that something would have to
be first installed before you can desire it to be purged.   :)

> Anyhow, dpkg is what you use to find out whether something's installed
> on your system or not.  It manages packages _locally_.  But it knows
> nothing about what packages are and are not available from package
> sources listed in /etc/apt/sources.list .  For that, use apt-get.

dpkg (on satan) seems to know a lot about packages that are available
via apt but that were never installed.  I can "-l" them, and I can even
"-p" them.

What dpkg _doesn't_ seem to know (until I actually install the package)
is -L, and similarly, it won't be able to do a -S search either.

I see my post generated some traffic.  I'll go take a look.  :)

Pete

-- 
Make everything as simple as possible, but no simpler. -- Albert Einstein
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