The list of installed packages is in
/var/lib/dpkg/status; that is the canonical reference. Installed packages are signalled in that file by their “install ok installed” status.
dpkg -l processes this file every time it’s run, and uses the information stored therein to produce its output.
If you want a simpler set of data to track, simplifying comparisons, you’ll have to generate it whenever necessary.
If you only want to track a list of installed packages, you can run
periodically and store its output in a file tracked with
git; since you also want versions,
might be more suitable.
As pointed out by Martin Konrad, if you want to be able to use the information generated here to restore the state of the system at a later date, you should also track the manually-installed markers, and I’d add the holds too:
You could add all the above to a
dpkg hook, to track all changes to your system; for example, using
/etc/packages/ to hold the files (rather than
/var/lib/dpkg, which is “owned” by
dpkg and should be left as-is), create a file named
post-invoke="if [ -x /usr/local/bin/package-history ]; then /usr/local/bin/package-history; fi"
and a file named
dpkg --get-selections > selections
dpkg -l > list
apt-mark showhold > holds
apt-mark showmanual > manual
The latter needs to be executable:
sudo chmod 755 /usr/local/bin/package-history
The outputs of all the commands above are sorted, so there’s no need to post-process them. With those files, you’ll be able to restore the installed package states exactly, track version changes, and also see packages which have been removed but not purged.
You can either add
git commit (checking for changes first) to the
package-history script, or use
etckeeper to track changes to the files in
/etc/packages, or even make
/etc/packages a git repository itself. Using a
dpkg hook ensures that the files will be updated with any package change, whether driven by
dpkg or any other tool piggy-backing on top of
dpkg. If you commit in the
package-history script itself, then the commit granularity will correspond to
dpkg executions; if you rely on
etckeeper, it will correspond to actions involving
To handle the commit in the script, add
if [ "$(git status --porcelain | wc -l)" -gt 0 ]; then
git add *
git commit -m 'Update package information'
to the end of the script above; you should then run it once manually, as root, to initialise the git history (after
mkdir /etc/packages; git init /etc/packages).