dpkg-query
- QUery packages installed
# List all non-free packages
dpkg-query -W -f='${Section}\t${Package}\n' | grep ^non-free
# List packages
dpkg-query --list
# List all non-free packages
dpkg-query -W -f='${Section}\t${Package}\n' | grep ^non-free
# List packages
dpkg-query --list