Ubuntu – How to completely remove virtual packages

aptpackage-managementserver

It turns out that removing a virtual package with apt-get only remove the package itself, leaving behind the real packages that were installed by it

So how do you remove a virtual package, along with all the real packages that it installs?

Best Answer

Use apt-cache depends to find a list of packages that the virtual package "contains" and then remove all of those in order to remove the virtual package. For example:

$ sudo apt-cache depends mono-complete
mono-complete
  Depends: mono-runtime
  Depends: mono-runtime-sgen
  Depends: libmono-2.0-1
  Depends: libmono-profiler
  Depends: mono-utils
  Depends: mono-jay
  Depends: mono-devel
  Depends: mono-mcs
  Depends: mono-csharp-shell
  Depends: mono-4.0-gac
  Depends: mono-4.0-service
  Depends: monodoc-base
  Depends: monodoc-manual
  Depends: libmono-cil-dev
  Depends: ca-certificates-mono

Now all you have to do is sudo apt-get remove all of the packages listed after Depends: and once done, the virtual package mono-complete will be removed automagically.

Run sudo apt-cache depends command first to take a look at all the dependent packages, and then, if the list of packages looks to you that it is ok to be removed, you can use this to remove them all:

$ sudo apt-get remove `apt-cache depends mono-complete | grep Depends | cut -d : -f 2`

Once the job is done, you can check virtual package status with:

$ dpkg -l mono-complete

It should be marked as (n)ot installed.

Related Solutions

Ubuntu – Why isn’t `auto-remove’ removing all unnecessary dependencies

As izx said, in his general answer, the first point, can be the cause of this sort of things.

Those dependencies are now also required/recommended by some other package(s) which are still installed on your system.

This is the most probable and valid reason for this kind of situation,But I am thinking that, the other packages named with clamav clamav-base clamav-freshclam libclamav6 libtommath0 most likely only associated with their mother package clamav. So, the first point, may not be the case in this particular situation.

The most likely cause of this problem, which seems to be the cause is, after installing the dansguardian package, you later installed all it's dependency packages by doing this kind of command below:

sudo apt-get install clamav clamav-base clamav-freshclam dansguardian libclamav6 libtommath0

If this is indeed the case, you can't uninstalled them by removing their mother package dansguardian. since in APT's language, they are installed "manually" as you explicitly installed these packages by feeding their name to the apt-get command, so must also uninstall them with explicitly stating their package name

You can check this, if it is the case by viewing /var/log/apt/history.log files.

To remove:

You must remove the installed packages by explicitly naming their name.So, in your specific situation it is

sudo apt-get purge clamav clamav-base clamav-freshclam dansguardian libclamav6 libtommath0

To see the dependent packages

You can find all the dependent packages with the below command:

apt-cache depends -i dansguardian | cut -f 2 -d ':' | tr '\n' ' '.

Note that, dansguardian depends on package libc6. while that package is very very essential one in your system. So, you can't remove all the dependency of dansguardian by generating their dependency package list with apt-cache command, hence it is not recommended. (actually, it is highly recommended to avoid doing that, unless you are happy with a broken system)

Ubuntu – How does APT choose the specific package to install in order to provide a virtual package needed as a dependency

How does APT choose the specific package to install in this case?

APT doesn't select a package. It tells:

You should explicitly select one to install.

If you try to manually select a package, it wouldn't be installed.

In the case of base-files depending on awk it is irrelevant. First, it actually PreDepends on awk, forcing dpkg to install awk before starting to install base-files; second, mawk have priority required which are installed at system installation, and apt nags you if you try to remove it. So, just don't do it.

Now, according to sources, apt tries first of satisfying the dependency before trying with virtual packages (i.e., if depends are firefox | www-browser, checks if any of the packages are installed, then try to install firefox if neither is). If the non-virtual package isn't available, it seems to just iterate over all packages which provides the virtual package, if no other dependencies are broken. Other comments evidence of this behavior are this which leads to GrpIterator::FindPreferredPkg function.