For example, I have "harden" package with every its dependencies (predependencies and recommendations) well-configured and other packages bad-configured (It's will be a good idea to preconfigure these packages again). And I want to reinstall my Debian system or install similar system on another computer.
To backup the debconf database (configdb) I simply run: debconf-copydb configdb newbackup --config=Name:newbackup --config=Driver:File --config=Filename:newbackup.dat
debconf-get-selections/debconf-set-selections solution will fully copy my old debconf db to my new debconf db but and I will have to manually run dpkg-reconfigure for a large amount of my packages. I think that it is not very convenient. There is another (3rd) solution: Copy answers for only one package by means of debconf-copydb: debconf-copydb configdb pkgbackup --owner <package name mask (regular expression)> --config=Name:pkgbackup --config=Driver:File --config=Filename:pkgbackup.dat And after reinstalling the Debian system run: debconf-copydb pkgbackup configdb --config=Name:pkgbackup --config=Driver:File --config=Filename:pkgbackup.dat But this solution has many disadvantages: 1) I don't remember exactly for what packages I have to save configuration (answers) and I recall this only after reinstalling 2) I want to save package configuration with all its dependencies's configuration and I will have to create full dependency list (with recommends) and run debconf-copydb configdb pkgbackup --owner <package name mask (regular expression)> for every dependency 3) I will not have 2 manners of preseed the debconf database (FALLBACK & OVERRIDE (see env vars DEBCONF_DB_FALLBACK & DEBCONF_DB_OVERRIDE))