How do I block a deb file from being installed as the result of a dependency?

Question

I'm running the latest version of Ubuntu 09.10 (syphyllitic sphinx or whatever the heck the codename is) and I'm trying to figure out how to block a package from installing as the result of a dependency. For this example, let's say that I would like to make it so bc is never installed, even though ubuntu-desktop claims to require it. Is there an easy way to make it so when I do an update and there is a new version of ubuntu-desktop it will never again try to install bc?

I think that this make be possible using some custom dummy packages and dpkg-divert or some such magic, but I just can't find some good docs on how to do it.

I'm also aware that doing something like this could cause a tear in the fabric of spacetime, but I'm willing to deal with that.

Answer 1

Check out the "equivs" package. You can fake up a package that pretends to offer whatever the real package you're installing needs.

Answer 2

This page from the Ubuntu wiki should fix your problem. It explains how to create a new metapackage without the uninstalled application.

Having said that, I just lived without the ubuntu-desktop metapackage.

Answer 3

i don’t know if it works for mandatory requirements, but it did a good job for me blocking the recommended package ttf-mscorefonts-installer when installing/upgrading wine.

i figured this package just exists to make the internet look crappy in order to keep young linux hackers from posing a threat to MS there.

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put the following into your /etc/apt/preferences:

Package: i-am-a-package-containing-junk
Pin: version *
Pin-Priority: -1

the Pin-Priority: -1 says that the matched versions of the matched packages should never be installed, while the rest matches every version of the package i-am-a-package-containing-junk, effectively preventing its installation.

Answer 4

I'm not aware of any simple way of doing this, and I doubt there is one. Dependencies are there for a reason after all, and the tools offer very little support for ignoring them.

As a matter of fact, even forcibly uninstalling a dependency (dpkg -r --force-depends <package>) will cause aptitude & friends to stop working until you fix the damage. So I'm afraid what you're asking is not possible, at least not with a simple command.

The simplest way to accomplish this is probably to create an empty package with a high version number, but even that might break when package dependencies change.

Could you explain what you're trying to do? Then maybe we can help.

Answer 5

in this specific case... don't use the metapackage- there's probably a 'core' package, and you can install what you need atop that- i had the same issue with xorg since i don't see the point of installing a nvidia drivers on an intel graphics based laptop- so i installed xorg-intel, rather than xorg-core.