How to list package dependees (reverse dependencies)?

Question

In order to research what caused the installation of a given package, I'd like to get a list of packages which depend on that package. I couldn't find anything obvious in man dpkg.

Answer 1

apt-cache rdepends packagename should do what you want

Answer 2

There are more than one way, with each method showing a different output.

For a detailed view of the dependency tree; aptitude install apt-rdepends apt-rdepends bash

Alternatively;

apt-cache showpkg bash

Or a concise list:

apt-cache rdepends bash

Answer 3

aptitude has a fairly nice way of handling this:

$ aptitude why bash
i   foomatic-filters PreDepends bash (>= 2.05)

It only lists one reason, but that's usually enough...

Answer 4

apt-cache showpkg

ex : apt-cache showpkg lightdm