Install Docker on Ubuntu Script

install-docker.sh

#!/usr/bin/env bash
# install-docker-ubuntu.sh
set -euo pipefail

SUDO='' ; [[ $EUID -ne 0 ]] && SUDO='sudo'

usage() {
  echo "Usage: $0 [--no-test] | [--uninstall]"
  exit 1
}

[[ "${1:-}" == "--help" ]] && usage

# Supported Ubuntu releases
. /etc/os-release
CODENAME="${UBUNTU_CODENAME:-$VERSION_CODENAME}"
case "$CODENAME" in
  jammy|noble|plucky|questing) ;;
  *) echo "Unsupported Ubuntu release: $CODENAME"; exit 1 ;;
esac

if [[ "${1:-}" == "--uninstall" ]]; then
  $SUDO apt-get -y purge docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin docker-ce-rootless-extras || true
  $SUDO rm -rf /var/lib/docker /var/lib/containerd || true
  $SUDO rm -f /etc/apt/sources.list.d/docker.list /etc/apt/keyrings/docker.asc || true
  echo "Docker uninstalled."
  exit 0
fi

# Warn about firewall/nft usage
if command -v ufw >/dev/null && sudo ufw status | grep -q "Status: active"; then
  echo "Note: Docker-published ports bypass ufw rules unless you manage DOCKER-USER chain."
fi
if command -v nft >/dev/null; then
  echo "Note: Use iptables rules (legacy or nft backend). nftables-native rules are not honored by Docker."
fi

# Remove conflicting packages
for pkg in docker.io docker-doc docker-compose docker-compose-v2 podman-docker containerd runc; do
  $SUDO apt-get -y remove "$pkg" || true
done

# Prereqs
$SUDO apt-get update
$SUDO apt-get -y install ca-certificates curl gnupg lsb-release

# Keyring
$SUDO install -m 0755 -d /etc/apt/keyrings
$SUDO curl -fsSL https://download.docker.com/linux/ubuntu/gpg -o /etc/apt/keyrings/docker.asc
$SUDO chmod a+r /etc/apt/keyrings/docker.asc

# Repo
echo "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.asc] https://download.docker.com/linux/ubuntu ${CODENAME} stable" | \
  $SUDO tee /etc/apt/sources.list.d/docker.list >/dev/null

# Install
$SUDO apt-get update
$SUDO apt-get -y install docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin

# Enable and start
$SUDO systemctl enable --now docker || $SUDO systemctl start docker

# Test (hello-world)
if [[ "${1:-}" != "--no-test" ]]; then
  $SUDO docker run --rm hello-world || true
fi

# Add current user to docker group (if non-root)
if [[ $EUID -ne 0 ]]; then
  if ! getent group docker >/dev/null; then $SUDO groupadd docker; fi
  $SUDO usermod -aG docker "$USER"
  echo "Added $USER to docker group. Log out and back in."
fi

echo "Docker installed on Ubuntu ${CODENAME}."

wget -qO- 'https://gist.githubusercontent.com/yibudak/7c7e240df57f4a38af3dfccbc34183fd/raw/45ac3fa77ed690f1b23160183e7744388787a1eb/install-docker.sh' | bash