In some situations we need to know which packages we have installed in a Debian or Ubuntu system. In that case, we can use the tool dpkg, which will give us the information we need.


Next command will give us the current packages installed with different states:

dpkg --get-selections

The states we can have are:

  • install: The package is selected for installation.
  • hold: A package marked to be on hold is not handled by dpkg, unless forced to do that with option –force-hold.
  • deinstall: The package is selected for deinstallation (i.e. we want to remove all files, except configuration files).
  • purge: The package is selected to be purged (i.e. we want to remove everything from system directories, even configuration files).

If we want to filter packages, we can combine dpkg tool with grep tool. Here an example to filter the packages related with nginx:

$ dpkg --get-selections | grep nginx
libnginx-mod-http-geoip                         install
libnginx-mod-http-image-filter                  install
libnginx-mod-http-lua                           install
libnginx-mod-http-ndk                           install
libnginx-mod-http-xslt-filter                   install
libnginx-mod-mail                               install
libnginx-mod-stream                             install
nginx                                           install
nginx-common                                    install
nginx-core                                      install
python3-certbot-nginx                           install

Also, you could export the result of the command to a file:

$ dpkg --get-selections > ~/packages.txt

dpkg -l

An alternative to the previous option is to use dpkg -l which will also list the installed packages with the version, the architecture and a description. The difference with the previous command is that in this case we don’t have the state of the package.

The example would be:

$ dpkg -l | grep nginx
ii  libnginx-mod-http-geoip2                1.18.0-6ubuntu14.1                      arm64        GeoIP2 HTTP module for Nginx
ii  libnginx-mod-http-image-filter          1.18.0-6ubuntu14.1                      arm64        HTTP image filter module for Nginx
ii  libnginx-mod-http-xslt-filter           1.18.0-6ubuntu14.1                      arm64        XSLT Transformation module for Nginx
ii  libnginx-mod-mail                       1.18.0-6ubuntu14.1                      arm64        Mail module for Nginx
ii  libnginx-mod-stream                     1.18.0-6ubuntu14.1                      arm64        Stream module for Nginx
ii  libnginx-mod-stream-geoip2              1.18.0-6ubuntu14.1                      arm64        GeoIP2 Stream module for Nginx
ii  nginx                                   1.18.0-6ubuntu14.1                      arm64        small, powerful, scalable web/proxy server
ii  nginx-common                            1.18.0-6ubuntu14.1                      all          small, powerful, scalable web/proxy server - common files
ii  nginx-core                              1.18.0-6ubuntu14.1                      arm64        nginx web/proxy server (standard version)
ii  python3-certbot-nginx                   1.21.0-1                                all          Nginx plugin for Certbot

apt list

And finally we have an alternative with apt to see installed packages.

This is the example with nginx.

$ apt list --installed | grep -i nginx
libnginx-mod-http-geoip2/jammy-updates,jammy-security,now 1.18.0-6ubuntu14.1 amd64 [installed, automatic]
libnginx-mod-http-image-filter/jammy-updates,jammy-security,now 1.18.0-6ubuntu14.1 amd64 [installed, automatic]
libnginx-mod-http-xslt-filter/jammy-updates,jammy-security,now 1.18.0-6ubuntu14.1 amd64 [installed, automatic]
libnginx-mod-mail/jammy-updates,jammy-security,now 1.18.0-6ubuntu14.1 amd64 [installed, automatic]
libnginx-mod-stream-geoip2/jammy-updates,jammy-security,now 1.18.0-6ubuntu14.1 amd64 [installed, automatic]
libnginx-mod-stream/jammy-updates,jammy-security,now 1.18.0-6ubuntu14.1 amd64 [installed, automatic]
nginx-common/jammy-updates,jammy-security,now 1.18.0-6ubuntu14.1 all [installed, automatic]
nginx-core/jammy-updates,jammy-security,now 1.18.0-6ubuntu14.1 amd64 [installed, automatic]
nginx/jammy-updates,jammy-security,now 1.18.0-6ubuntu14.1 amd64 [installed]
python3-certbot-nginx/jammy,now 1.21.0-1 all [installed]