docker power

#!/usr/bin/env bash
set -Eeuo pipefail

# Usage:
#   chmod +x setup-power-user-docker.sh
#   ./setup-power-user-docker.sh
#
# What it does:
# - verifies Ubuntu/Debian-like system
# - installs Docker from distro packages if missing
# - ensures your current user is in sudo group
# - ensures your current user is in docker group
# - enables and starts Docker
# - prints what to do next

if [[ "${EUID}" -eq 0 ]]; then
  echo "Do not run this script as root."
  echo "Run it as your normal user. It will use sudo when needed."
  exit 1
fi

USER_NAME="${SUDO_USER:-$USER}"

need_cmd() {
  command -v "$1" >/dev/null 2>&1 || {
    echo "Missing required command: $1"
    exit 1
  }
}

need_cmd sudo
need_cmd getent
need_cmd id

echo "[1/6] Detecting OS..."
if [[ -r /etc/os-release ]]; then
  . /etc/os-release
  echo "Detected: ${PRETTY_NAME:-unknown}"
else
  echo "Cannot detect OS. /etc/os-release not found."
  exit 1
fi

echo "[2/6] Updating package index..."
sudo apt-get update

echo "[3/6] Installing Docker if needed..."
if ! command -v docker >/dev/null 2>&1; then
  sudo apt-get install -y docker.io
else
  echo "Docker already installed: $(docker --version || true)"
fi

echo "[4/6] Ensuring groups exist..."
getent group sudo >/dev/null || sudo groupadd sudo
getent group docker >/dev/null || sudo groupadd docker

echo "[5/6] Adding user '${USER_NAME}' to required groups..."
if id -nG "${USER_NAME}" | grep -qw sudo; then
  echo "User already in sudo group."
else
  sudo usermod -aG sudo "${USER_NAME}"
  echo "Added ${USER_NAME} to sudo group."
fi

if id -nG "${USER_NAME}" | grep -qw docker; then
  echo "User already in docker group."
else
  sudo usermod -aG docker "${USER_NAME}"
  echo "Added ${USER_NAME} to docker group."
fi

echo "[6/6] Enabling Docker service..."
sudo systemctl enable docker
sudo systemctl start docker

echo
echo "Done."
echo
echo "Important:"
echo "1. Log out and log back in, or run: newgrp docker"
echo "2. Then test with:"
echo "   docker run hello-world"
echo
echo "Current group membership for ${USER_NAME}:"
id "${USER_NAME}"