sudo -u postgres psql -c "show data_directory" and it shows
/var/lib/postgresql/9.5/main. If I understand correctly, this is the directory that stores the database files.
sudo apt-get purge postgr*. Did this remove the database files?
sudo apt-file list postgresql did not show
/var/lib/postgresql in its entries, which means it shouldn't have purged those files, right?
The reason I'm asking is that I'm not exactly sure what data there was in the database and running
ls -l /var/lib/postgresql is showing "time modified" around the time that I purged postgresql on all files.