Re: [SLUG] Ubuntu questions

From: Paul M Foster (paulf@quillandmouse.com)
Date: Fri Jan 20 2006 - 16:06:29 EST


eben1@tampabay.rr.com wrote:
> Gah, I hate webmail. Gotta get pine working.
>
> From: Sick Twist <thesicktwist@hotmail.com>
> Date: Friday, January 20, 2006 9:12 am
>
>
>>>From: eben1@tampabay.rr.com
>>>Date: Fri, 20 Jan 2006 01:48:22 -0500

<snip>

>>>1. How do I use apt-*? I've used strictly rpm since the mid 1990s.
>>
>>apt-get update
>>apt-cache search epiphany
>>apt-get install epiphany-browser
>>apt-get upgrade epiphany-browser
>>apt-get upgrade
>
>
> Cool, thanks. How do I install a .deb file?
>

Assuming you have an isolated .deb file you picked up off the internet
somewhere, you can install it via:

dpkg -i something.deb

Normally you wouldn't do this. Instead, you'd get a package from a
Debian repository. In that case, it would be:

apt-get install something

The /etc/apt/sources.list file designates the repositories of packages
that your apt/dpkg will look in to find a packages. You can update the
listing of available packages via:

apt-get update

If you want to browse and pick and choose packages, there are three ways
to do it: 1) dselect. This is a primitive, horrible tool, but it does
allow you to browse and select packages; 2) aptitude. This is a console
app that basically does the same thing as dpkg but in a much more
user-friendly way; 3) synaptic. This is the GUI version of the above. I
don't like synaptic, because I've had problems with it in the past, but
it is the official GUI way to do it. In all three of these programs, you
can update your package list, look at descriptions of the packages,
select them, and install them. Ubuntu or other repositories are the same
type of thing as official Debian repositories. You just put the proper
data for that repository in your sources.list file, and update.

>
>>>2. I like fvwm2 as a window manager, but cannot find it in the
>>>list of packages offered by Synaptic. Same with a couple more
>>>programs. Should I go ahead and compile them from source? Is
>>>there an "official" way, so that the database knows about them?
>>

You *can* build a package from source, but unless you build your
completed package into a .deb file, apt et al will not know it's there.
In fact, it won't be enough to build it into a .deb file; you'll need to
install that .deb file for apt to twig that the program is there. I
believe there are some programs out there designed to take a source
distribution and turn it into a .deb file. However, the more serious
issue will be whether you have a actual libraries and other junk on your
system necessary to build the package you want.

>>apt-get uses repositories which are groups of packages (binary or
>>source) that can be automatically installed from the Internet.
>>The configuration file for the repositories to use is
>>/etc/apt/sources.list. Check out the man page for sources.list
>
>
> Pretty Greekish (the man page, not your explanation). I assume
> once I become more familiar with The Debian Way it'll become more
> comprehensible.
>

Well, yeah. But you know how man pages are. They're great for people who
already know the basic idea. They're better for reference than anything
else.

> I did uncomment some other repositories already in
> /etc/apt/sources.list. More packages were installable, but sadly
> not pine or fvwm2. For now I'm using metacity (like "metadata", or
> like "metastasize"?) because it doesn't have all the doodads of
> Gnome or KDE.
>

I don't see fvwm2 in the Debian stable->unstable archives. I see fvwm1
and fvwm95. Pine will never be included in Debian because there are
licensing issues with the University of Washington (the makers of pine).
When I found I couldn't get pine from Debian years ago, I switched to
mutt. It's actually a better program, much more configurable. There are
various examples of good ~/.muttrc files out on the net (that's the
config file for mutt).

>
>>Basically the structure is this:
>>A B C D1 [D2 ...]
>>
>>A - type of packages (usually deb or deb-src)
>>B - address of repository
>>C - name of release (e.g. breezy)
>>D - one or more types of packages to be included (Ubuntu uses main,
>>restricted, universe and multiverse to group packages based on
>>their degree
>>of security updates, legal status, etc).
>>
>>Here is an example line from my sources.list file:
>>deb http://archive.ubuntu.com/ubuntu breezy main restricted
>>universe
>>multiverse
>

Official Debian repositories look like this in your sources.list file:

deb ftp://ftp.us.debian.org/debian stable main contrib non-free

Same scheme as above, but you can substitute "testing" or "unstable" in
place of "stable" above, and you can have all three in your sources.list.

>
> Is there any kind of priority associated with the package type order?
>

Yes, but you don't want to know how it works. If you really must know,
you can look at the man file for apt_preferences. Or search on the
internet for "apt pinning". That's what it's called: "pinning". It
allows you to do a variety of things, including holding back a package
from being updated even if there's a newer version. It also allows you
to select a specific version of a package (stable/testing/unstable) even
if you have all three Debian versions (stable/testing/unstable) in your
sources.list file. You have to configure a specific file (by hand) to do
this, and the logic is byzantine.

>
>>As Tyler already mentioned, Debian (and hence Ubuntu) occasionally
>>make use of "metapackages" to allow the user to easily install
>>a group of packages. The metapackage does not actually contain
>>any files itself, so removing it does no harm.
>
>
> Until you go to do a dist-upgrade, right?

I'd strongly suggest *not* doing dist-upgrade. It will wholesale upgrade
all your packages, and may in fact purge packages without you being
aware of it. When you go to run it, the package is gone. This has
happened before. A few years ago, all of KDE was in flux in Debian, and
for a time, if you weren't careful, apt/aptitude would delete KDE packages.

Every time dselect or aptitude (or apt) goes to update or install
packages, it should tell you what other packages will be installed,
deleted or upgraded along with your actual selection. Pay attention to
this, and make sure nothing you really want gets whacked. Package
management is imperfect, no matter who's doing it (Red Hat, SuSE,
Debian), and you can get into trouble if you carelessly accept what
programs tell you they're going to do. In fact, more than once I've
gotten into circular dependency problems that took hours to resolve.

>
> What about the threatened OS failure? Is that for real?
>
>
>>>I'm sure I'll have more, as I haven't done a complete upgrade like
>>>this in years.
>
>
>>Well now that you have a Debian-based distro you have no reason to
>>wait years for upgrades. :)
>
>
> I think I detected irony there...

I'm sure it was meant as humor, but there is a definite plus side to the
Debian way of doing things: instead of having to reinstall every time a
new version comes out, you can gradually upgrade packages as you like
and still maintain a working system.

Sorry if I've over-explained things. I haven't followed this thread, but
this particular post jumped out at me. Apologies if I've explained
something already clearly covered earlier.

Paul

-- 
Paul M. Foster
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