Instale docker.io no Ubuntu 18.04

Question

De acordo com isso:

https://linuxconfig.org/how-to-install-docker-on-ubuntu-18-04-bionic-beaver

Devo conseguir instalar o Docker usando:

apt install docker.io

No entanto, como root, recebo:

apt install docker.io
No command 'apt' found, did you mean:
 Command 'aptd' from package 'aptdaemon' (main)