Managing unofficial repositories on a Debian system

Question

A few years ago I added this repository to my sources.list:

http://www.deb-multimedia.org/

because it contained packages like acroread or flash player, which were either missing or out of date in the official repos.

However, now I have just realized that some of the packages from that repository are broken, e.g. mencoder. Hence a few questions:

1. How can I find out which packages are installed from this particular repository?
2. How can I make this repository lower priority, so that only the packages I want are automatically installed/upgraded from there?

EDIT: I edited `/etc/apt/preferences' file as someone suggested:

grzes:/home/ga# cat /etc/apt/preferences
Package: *
Pin: release a=testing
Pin-Priority: 700

Package: *
Pin: release a=stable
Pin-Priority: 600

Package: *
Pin: release a=unstable
Pin-Priority: 50

Package: *
Pin: origin deb-multimedia.org/
Pin-Priority: 50

but it didn't seem to work (note that I downgraded this package manually):

grzes:/home/ga# apt-cache policy mencoder
mencoder:
  Installed: 2:1.0~rc4.dfsg1+svn34540-1+b2
  Candidate: 3:1.1-dmo5
  Version table:
     3:1.1-dmo5 0
         50 http://www.deb-multimedia.org/ unstable/main i386 Packages
        700 http://www.deb-multimedia.org/ testing/main i386 Packages
 *** 2:1.0~rc4.dfsg1+svn34540-1+b2 0
         50 http://ftp.uk.debian.org/debian/ unstable/main i386 Packages
        700 http://ftp.uk.debian.org/debian/ testing/main i386 Packages
        100 /var/lib/dpkg/status
     2:1.0~rc3++final.dfsg1-1 0
        600 http://ftp.uk.debian.org/debian/ stable/main i386 Packages

Answer 1

I don't know how to list all packages and their repositories, but for a single one you can just execute apt-cache policy <package>. The line with the *** is the currently installed version with the corresponding repositories.

Setting the priority of a particular source is called apt pinning and can be done via /etc/apt/preferences (newer Ubuntu versions require the configuration to be in /etc/apt/preferences.d/ instead!):

You can pin either per release, origin or version. In your case, you want to pin either per origin:

Package: *
Pin: origin www.deb-multimedia.org
Pin-Priority: 300

or per release and the o= option:

Package: *
Pin: release o=Unofficial Multimedia Packages
Pin-Priority: 300

Note: It seems like the first matching pin configuration is used and additional matching configurations are ignored.

To see all currently known package sources, their priority, origins and other attributes, just call apt-cache policy without any option.

Answer 2

You can use the script apt-show-versions.

apt-show-versions -b | grep deb-multimedia

would give you a list of packages from deb-multimedia.org.

Answer 3

It turns out that you can't have both the origin and release clauses at the same time. Every repository provides a label though, which can be used for filtering. In my case the correct /apt/cache/preferences file looks like this:

Package: acroread acroread-data acroread-debian-files acroread-dictionary acroread-dictionary-en acroread-escript acroread-fonts-jpn acroread-l10n acroread-l10n-en acroread-plugin-speech acroread-plugins cinelerra flashplayer-mozilla mozilla-acroread w32codecs
Pin: release a=testing,l=Unofficial Multimedia Packages
Pin-Priority: 550

Package: acroread cinelerra flashplayer-mozilla mozilla-acroread w32codecs
Pin: release a=stable,l=Unofficial Multimedia Packages
Pin-Priority: 500

Package: *
Pin: origin "www.deb-multimedia.org"
Pin-Priority: 50

Package: *
Pin: release a=testing
Pin-Priority: 700

Package: *
Pin: release a=stable
Pin-Priority: 600

Package: *
Pin: release a=unstable
Pin-Priority: 50

To get the list of all available labels you need to run:

apt-cache policy

without specifying package name.