CODEWITHSUNDEEP
debianpackage-managersdpkg
yaobin
yaobin

Reputation: 2526

What is the "package selection data" in Debian's package management system?

I'm learning Debian's package management system and have read Chapter 2. Debian package management. But I have difficulty in understanding the concept of "selection", or maybe "package selection". More specifically:

For example, whenever I want to find whether I have a package installed on my system, I usually run dpkg --get-selections 'PACKAGE-NAME'. Frankly speaking, I don't know exactly why the option is called get-selections and why I should use it. I turned to dpkg manpage, but it doesn't explain further. The chapter above doesn't seem to explain, either.

While I'm reading the Debian reference, I see another tool called dselect which also helps manage the packages. I'm also curious why it is called "select", and this may be a hint to understanding the concept of "selection".

According to my current research, I have some guesses of what it is about:

However, the understandings above don't look right because that seems to be solved by using the symbolic links.

Hope someone would explain it to me. Thanks for the help!

Upvotes: 0

Views: 136

Answers (1)

Giacomo Catenazzi
Giacomo Catenazzi

Reputation: 9533

If you write dpkg --get-selections (this command is often included in crontab so that we backup the actual package installed on a machine), you get the list of all packages, installed, and deinstalled (but not purged).

So the selection is one of the status of the package:

  • install: the package is installed
  • deinstall: the package is no more installed (but config file are keep, so the package is not like non installed (or purged) packages). The dpkg still keep track of config files.

As far I know, you can tell dpkg also to install, hold, deinstall or purge (--set-selections)

This is a sort of selection, so the name. There are other statuses (successfull installed, error on postinst, error on untar, ...).

Note: Debian Reference Manual is a very old manual, grown "organically". Feel free to fill a bug (minor or wish), so that volunteers can improve it.

Upvotes: 2

Related Questions