Debian – Is it possible to simulate installation of Debian packages, and still marking them as installed

The base system is described in Debian policy as all packages with required or important priority.

You can search for the packages that the required and important priorities are attached to with the aptitude utility.

aptitude search ~prequired -F"%p"
aptitude search ~pimportant -F"%p"

debootstrap installs these packages during the setup process.
tasksel will then install whatever other roles you choose on top, normally standard is the default selection that is used.

On top of what is listed in the base system you will get

• A Kernel (thankfully)
• Input/Locale/Dictionary packages.
• Hardware packages. (ACPI, USB, PCI, Virtual guest additions on vm's)
• Then some dependent libraries to support the above.

This amounts to about 60 packages on my VirtualBox VM (without the VBox guest additions which pull in a lot of dependencies).

Run the Expert Install (select "Advanced options > Expert") if you get a chance. It gives you a better idea of the step by step install process and when apt is being run outside of the base install.

I don't know of a one-stop command line solution, although all the tools exist (apt-cache depends --installed, apt-cache rdepends --installed --recurse, apt-mark showmanual, dpigs, etc.). It would be possible to hack together a command line script that could attempt to find large packages with few manually installed reverse dependencies. Here's the proof of concept I used as a starting point:

dpigs | awk 'NR == 1 {print $2}' | xargs apt-cache rdepends --installed --important --recurse | awk '!/:/ {print $1}' | sort -u

On the other hand, if you want to do complex analysis of the graph in multiple directions (e.g., what set of manually installed packages has the largest on-disk overlapping set of recursive dependencies), it can quickly get out of hand. At that point, you'll probably need to look at something more customizable (awk or python?).

Full Disclosure: I have contributed to the project below. If that kind of thing matters to you, please take it into account. If I were aware of a similar project that were already in the Debian repositories, I would probably post that instead.

While I prefer to do everything from the command line, you might find pacgraph (also on github) a useful alternative. It was originally written by Kyle Keen for Arch Linux, but it's now compatible with deb- and rpm- based systems as well. I used to have some sample output from an Ubuntu system, but I can't find it, so here's an example from his web site:

.

It's been a while since I've used it, but I believe there are also flags to highlight a particular package, with different colors for its recursive dependencies and reverse dependencies.