Install Docker and docker-compose on Ubuntu 20.04

install_docker.sh

# install docker
sudo apt update
sudo apt -y install apt-transport-https ca-certificates curl software-properties-common
curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -
sudo add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu focal stable"
sudo apt update
apt-cache policy docker-ce
sudo apt -y install docker-ce
sudo chmod 666 /var/run/docker.sock
docker ps

# install docker-compose
sudo curl -L "https://github.com/docker/compose/releases/download/1.27.4/docker-compose-$(uname -s)-$(uname -m)" -o /usr/local/bin/docker-compose
sudo chmod +x /usr/local/bin/docker-compose
docker-compose --version

Use this command to install complete version of docker

apt install docker-ce docker-ce-cli containerd.io docker-compose-plugin

This is working download link:
sudo curl -L "https://github.com/docker/compose/releases/download/v1.27.4/docker-compose-$(uname -s)-$(uname -m)" -o /usr/local/bin/docker-compose

The author forgot to add "v" for version of docker-compose.