Difference between dpkg -l and apt list

Question

I have spin up a new amazon ubuntu machine for installing docker.

When I type apt list | grep docker I am getting the below output.

root@ubuntu:/home/rhost1/Desktop# apt list | grep docker

WARNING: apt does not have a stable CLI interface. Use with caution in scripts.

cockpit-docker/xenial-backports,xenial-backports 148-1~ubuntu16.04.1 all
docker/xenial 1.5-1 amd64
docker-ce/xenial 17.06.2~ce-0~ubuntu amd64 [upgradable from: 17.06.0~ce-0~ubuntu]
docker-compose/xenial-updates,xenial-updates 1.8.0-2~16.04.1 all
docker-doc/xenial-updates,xenial-updates 1.12.6-0ubuntu1~16.04.1 all
docker-registry/xenial 2.3.0~ds1-1 amd64
docker.io/xenial-updates 1.12.6-0ubuntu1~16.04.1 amd64
golang-docker-dev/xenial-updates,xenial-updates 1.12.6-0ubuntu1~16.04.1 all
golang-github-docker-containerd-dev/xenial-updates,xenial-updates 0.2.5-0ubuntu1~16.04.1 all
golang-github-docker-distribution-dev/xenial,xenial 2.3.0~ds1-1 all
golang-github-docker-docker-dev/xenial-updates,xenial-updates 1.12.6-0ubuntu1~16.04.1 all
golang-github-docker-go-units-dev/xenial,xenial 0.3.0-1 all
golang-github-docker-libkv-dev/xenial,xenial 0.1.0-2 all
golang-github-docker-libtrust-dev/xenial,xenial 0.0~git20150526.0.9cbd2a1-1 all
golang-github-docker-notary-dev/xenial,xenial 0.1~ds1-1 all
golang-github-docker-spdystream-dev/xenial,xenial 0.0~git20151103.0.4d80814-1 all
golang-github-fsouza-go-dockerclient-dev/xenial,xenial 0.0+git20150905-1 all
golang-github-opencontainers-runc-dev/xenial-updates,xenial-updates   1.0.0~rc2+docker1.12.6-0ubuntu1~16.04.1 all
golang-github-samalba-dockerclient-dev/xenial,xenial 0.0~git20150905.0.77b723e-1 all
kdocker/xenial 4.6-2 amd64
libnss-docker/xenial 0.01-1 amd64
ovn-docker/xenial-updates 2.5.2-0ubuntu0.16.04.1 amd64
python-docker/xenial-updates,xenial-updates 1.9.0-1~16.04.1 all
python-dockerpty/xenial-updates,xenial-updates 0.4.1-1~16.04.1 all
python3-docker/xenial-updates,xenial-updates 1.9.0-1~16.04.1 all
python3-dockerpty/xenial-updates,xenial-updates 0.4.1-1~16.04.1 all
ruby-docker-api/xenial,xenial 1.22.2-1 all
runc/xenial-updates 1.0.0~rc2+docker1.12.6-0ubuntu1~16.04.1 amd64
systemd-docker/xenial 0.2.1+dfsg-1 amd64
vim-syntax-docker/xenial-updates,xenial-updates 1.12.6-0ubuntu1~16.04.1 all

Where as docker commands confirms that docker is not installed at all.

Same is double checked, when I have typed dpkg -l | grep docker, even it is not showing any docker packages.

Why apt list | grep docker is showing the packages? what do they exactly mean?

Note: ubuntu version is ubuntu-xenial-16.04-amd64.

Answer 1

apt list will show all available packages. If you need to get list of installed packages then use

apt list --installed

If you want to install docker

curl -SsL https://get.docker.com | sh

After that you need to start docker

systemctl enable docker
systemctl start docker