Handling Debian packages

Here are a few not-quite-so-basics for dealing with Debian packages including some pointers on how to put packages on hold or how to setup a local repository.

Putting a package on hold

There are reasons for not wanting to automatically upgrade a package, for instance if you know that the new version is buggy. In that situation you want to put this package on hold:

echo packagename hold | dpkg --set-selections

An apt-get dist-upgrade now won't update this package anymore. To release a package from hold again:

echo packagename install | dpkg --set-selections

To learn about the packages that are on hold:

dpkg --get-selections

Local Repository

Individual packages can be installed via dpkg -i package.deb. This won't, however, take care of dependencies. If you have lots of those packages you might want to have a local repository that you can add to sources.list and use in conjunction with commands as apt-get dist-upgrade.
First, create a directory repository (change the name to your liking) together with two subdirectories binary and source (optional):

mkdir -p repository/binary repository/source

Now, you can copy your .deb packages to repository/binary and your source files such as .dsc, .orig.gz, .diff.gz to repository/source. Next, you need to generate information about these files:

cd repository
dpkg-scanpackages binary /dev/null \
  | gzip -9c > binary/Packages.gz
dpkg-scansources source /dev/null \
  | gzip -9c > source/Sources.gz

Finally, to make the freshly created repository available to e.g. apt-get add the following to /etc/apt/sources.list:

deb file:///data/repository binary/
deb-src file:///data/repository source/

Downgrading a package

To install a particular version of a package:

sudo apt-get install packagename=version

Older versions of packages can be found for example at http://snapshot.debian.net.

Typical errors

When you use packages from third-parties that are not official part of a distribution it's likely that you run into errors. For instance:

sudo apt-get install …
…
dpkg: error processing packageX.deb (--unpack):
 trying to overwrite …, which is also in package …
dpkg-deb: subprocess paste killed by signal (Broken pipe)
Errors were encountered while processing:
 packageX.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)

If you know what you're doing (ie. that this isn't a serious issue) you can work around as:

dpkg -i --force-overwrite packageX.deb