# setup-auto-updates.sh

A cross-compatible shell script for enabling unattended automatic updates on Debian and Ubuntu systems.  
Designed for clean, predictable configuration using modern `Origins-Pattern` syntax.  
Includes dry-run validation and systemd timer setup when supported.

---

**Version:** 2025-07-28  
**License:** MIT

---

## Features

- Detects Debian or Ubuntu and applies best-practice configuration
- Configures `unattended-upgrades` to install regular and security updates automatically
- Clears legacy `Allowed-Origins` and uses clean `Origins-Pattern` format
- Supports both traditional and deb822-style APT sources
- Enables systemd timers (`apt-daily.timer` and `apt-daily-upgrade.timer`) when available
- Configures daily update checks, weekly autoclean, and auto-reboot at 4:00 AM if needed
- Includes a dry-run validation with basic error detection
- Prompts to delete the script after successful execution

## Compatibility

- **Debian**: Bookworm, Trixie, and newer
- **Ubuntu**: Noble (24.04 LTS) and newer
- Should be safe on any modern system with `unattended-upgrades` and `apt`

## What It Does

- Installs `unattended-upgrades` if missing
- Writes a new `/etc/apt/apt.conf.d/50unattended-upgrades` using a robust and portable structure
- Enables APT periodic updates via `/etc/apt/apt.conf.d/20auto-upgrades`
- Enables systemd timers if `systemctl` is available
- Does **not** run any updates itself or reboot your system directly

## Kernel Update Policy

By default, this script **permits installation of updated kernels** if they match the configured origins (e.g., `-updates`, `-security`).  
If you prefer to exclude kernel packages from automatic updates, add the following to `/etc/apt/apt.conf.d/50unattended-upgrades`:

```conf
Unattended-Upgrade::Package-Blacklist {
    "linux-image";
    "linux-headers";
};
```

## Example Output

```sh
[INFO] Unattended-upgrades configurator (Debian/Ubuntu)
[INFO] Detected OS: Debian GNU/Linux 12 (bookworm)
[INFO] Updating APT cache…
[INFO] Installing unattended-upgrades…
[INFO] Validating unattended-upgrades with a dry run…
Allowed origins are: origin=Debian,archive=bookworm, origin=Debian,archive=bookworm-updates, ...
[INFO] Timers:
Mon 2025-07-28 06:40:14 MDT ... apt-daily-upgrade.timer
Mon 2025-07-28 10:51:12 MDT ... apt-daily.timer
[OK] Unattended updates configured. Regular + security updates will apply automatically; reboot at 04:00 if needed.
```

## Usage

```bash
sudo ./setup-auto-updates.sh
```

- Must be run as root
- Prompts to delete itself after successful configuration if run interactively

## Customization

- **Reboot Time:**  
  ```bash
  sudo REBOOT_TIME="03:30" ./setup-auto-updates.sh
  ```
- **Exclude Third-Party Updates:**  
  Use `/etc/apt/apt.conf.d/60unattended-thirdparty` to add `site=...` patterns.

## Systemd Timers Enabled

- `apt-daily.timer` – Regular APT metadata refresh  
- `apt-daily-upgrade.timer` – Executes `unattended-upgrades` daily  

## Self-Delete Behavior

At the end of the script, you’ll be asked:

> Script successful. Do you wish to delete this script?

This helps keep your directory tidy after one-time provisioning.

## Limitations

- Does not configure granular package pinning or holds  
- Does not auto-install non-origin packages (e.g., third-party repos) unless explicitly configured  
- Power-check skipped (optional `powermgmt-base` not installed)  
- Not compatible with non-Debian-based distributions (e.g., Fedora, Arch)

## License

MIT License – use freely, modify as needed, no warranties.

---

Created and maintained by a privacy-conscious, security-oriented Linux sysadmin.