Re: what's the use of dselect
Wasn't linux (also) all about acomplishing one task in many different ways?
Leo Custodio
aliensprite@hotmail.com
http://members.rogers.com/aliensprite/
-----BEGIN PGP PUBLIC KEY BLOCK-----
Version: 2.6.2
mQCNAz/nyswAAAEEAM1Jl14YqNlrUGmr4vh5OKGbDg5qiFnY/Ioqa5j5j9jlTsiH
7EJNlhIvu5OV223D0REUmWbFaKBQlnZAaDRRROb52YPuZ8NQfyu/C5zvTz8qubEx
jWn+nYryqKZxQsDwjntkNIMxx5n+QB7WhDltenCFE/VxYhsTa59EWqUqkz/RAAUR
tC5MZW9uYXJkbyBDLiBDdXN0b2RpbyA8YWxpZW5zcHJpdGVAaG90bWFpbC5jb20+
=xAh5
-----END PGP PUBLIC KEY BLOCK-----
----- Original Message -----
From: "Benedict Verheyen" <linux4bene@pandora.be>
To: <debian-user@lists.debian.org>
Sent: Thursday, February 19, 2004 6:13 PM
Subject: what's the use of dselect
> Hi,
>
> I admit i'm a little confused as to what the use is of dselect when
> we have tools like aptitude and apt-get.
> Off course, if you like dselect, stop reading ;)
> I don't like it so i try to use other tools to accomplish the same
> stuff you can do with dselect.
> To try to figure this out,i looked at dselect, dpkg, apt-get and aptitude.
> According to the manpages of the aformentioned packages, the tools
> match up like this:
>
> Package Manager: dpkg
> Backend Tool: apt-get
> Frontend Tools: dselect, aptitude, synaptic, etc
>
> By looking at the manpages, i first looked at what files the tools
> use:
>
> 1) Dpkg
> /var/lib/dpkg/status: status of packages
> /var/lib/dpkg/available: available packages
>
> 2) Apt
> /var/lib/apt/lists: available packages
> /var/cache/apt/archives: saved/cached packages
>
> 3) Dselect
> /var/lib/dpkg/available
>
> 4) Aptitude
> /var/lib/aptitude/pkgstatus status of packages
>
> 1. Now, the manpage of apt-get says this about /var/lib/apt/lists
> "/var/lib/apt/lists/
> Storage area for state information for each package resource specified
> in sources.list(5) Configuration Item: Dir::State::Lists. "
> This seems to be incorrect as the files in that dir seem to be
> about what packages are available on what location and not what
> the status of the package is on the system.
>
> 2. /var/lib/dpkg/available seems the same as /var/lib/apt/lists.
> But to get the same in both files, you also need to do a
> dselect update (as opposed to a apt-get update)
>
> 3. Something that wasn't clear for me: where does an "apt-cache policy"
> command gets it's info?
>
> 4. If you do an "apt-get update", then i think aptitude knows
> about the updated lists.
>
> So as to what is the use of dselect:
>
> For the common daily use, apt-get and aptitude seem to do the job.
> The only situation i can think of where you'll need dselect is
> after a dpkg --set-selections < myselection.
> Because this changes the status of the packages and thus the
> /var/lib/dpkg/status file. "apt-get dselect-upgrade" is the
> command you should run to update the system and not
> "apt-get dist-upgrade".
>
> Why can't use apt-get in this situation (well according to me)?
> Because apt-get doesn't use the file /var/lib/dpkg/status.
> So it will probably just upgrade the system and not install
> for instance the new packages that where set by
> dpkg --set-selections.
>
> But, in order to do this correctly, you'll have to make sure
> that your sources.list matches the one from the source system
> (to have the same packages available) and that you've done
> a dselect update. That will make sure /var/lib/dpkg/available
> is in working order.
> apt-get dselect-upgrade then calls dselect to install the
> packages. So the versions of the available packages need to be
> known before we can change their status with dpkg --set-selections.
>
> So if the above is true, wouldn't it make sense for apt-get
> to do like dselect and use /var/lib/dpkg/available or would that
> typically be more of a job for a frontend tool like aptitude?
> If so, is there a similar command in aptitude for
> "apt-get dselect-upgrade" ? Or does it also use dselect to do this?
> It wouldn't make sense that if those tools are ment to replace
> dselect that they would still use dselect for some stuff.
> And frankly i find it confusing :)
>
> Any comments are appreciated.
>
> Benedict
>
>
> --
> To UNSUBSCRIBE, email to debian-user-request@lists.debian.org
> with a subject of "unsubscribe". Trouble? Contact
listmaster@lists.debian.org
>
Reply to: