# Debian Network Reinstall Script

## Introduction

This script is used to reinstall the Linux OS of a KVM-based VPS or a Hyper-V virtual machine to Debian 10 Buster.

## How It Works

1. Generate a preseed file to automate installation
2. Download the 'Debian-Installer' to the `/boot` directory
3. Append a menu entry of the installer to the GRUB2 configuration file

## Usage

    sudo bash -c "$(curl -fsSL https://github.com/bohanyang/debi/raw/master/debi.sh)" -- <OPTIONS>

## Available Options

 - `--preset <string>` Shortcut for applying [preset options](#presets)
 - `--ip <string>` Static public/private IP, e.g. `10.0.0.2`
 - `--netmask <string>` e.g. `255.255.255.0` /  `ffff:ffff:ffff:ffff::`
 - `--gateway <string>` e.g. `10.0.0.1`
 - `--dns '8.8.8.8 8.8.4.4'` Ignored if `--ip` is not specified. Quoted string where IP addresses are seperated by spaces
 - `--hostname debian`
 - `--installer-password <string>` Enable installer network console to monitor installation status. e.g. `ssh installer@10.0.0.2`
 - `--authorized-keys-url <string>` Setup SSH public key authentication for the new user and enable installer network console. e.g. `https://github.com/bohanyang.keys`
 - `--suite buster`
 - `--mirror-protocol http` or `https` or `ftp`
 - `--mirror-host deb.debian.org`
 - `--mirror-directory /debian`
 - `--security-repository http://security.debian.org/debian-security` Magic value: `'mirror' = <mirror-protocol>://<mirror-host>/<mirror-directory>/../debian-security`
 - `--skip-account-setup`
 - `--username debian` New user with `sudo` privilege or `root`
 - `--password <string>` New user password to set. **Will be prompted if not specified here**
 - `--sudo-no-password` Make the user run "sudo" commands without entering the password
 - `--timezone UTC` https://en.wikipedia.org/wiki/List_of_tz_database_time_zones#List
 - `--ntp 0.debian.pool.ntp.org`
 - `--skip-partitioning`
 - `--partitioning-method regular`
 - `--disk <string>` Manually select a boot disk when more than one disk is available. e.g. `/dev/sda`
 - `--force-gpt` Create a *GUID Partition Table* **(Default)**
 - `--no-force-gpt`
 - `--bios` Don't create *EFI system partition*. If GPT is being used, create a *BIOS boot partition* (`bios_grub` partition). Default if `/sys/firmware/efi` is absent. [See](https://askubuntu.com/a/501360)
 - `--efi` Create an *EFI system partition*. Default if `/sys/firmware/efi` exists
 - `--filesystem ext4`
 - `--kernel <string>` Choose an package for the kernel image
 - `--cloud-kernel` Choose `linux-image-cloud-amd64` as the kernel image
 - `--no-install-recommends`
 - `--install 'ca-certificates libpam-systemd'` Additional packages to install. Quoted string where package names are seperated by spaces. **Package names specified here will override the default list, rather than append to it**
 - `--safe-upgrade` **(Default)** `apt upgrade --with-new-pkgs`. [See](https://salsa.debian.org/installer-team/pkgsel/-/blob/master/debian/postinst)
 - `--full-upgrade` `apt dist-upgrade`
 - `--no-upgrade` 
 - `--eth` Disable *Consistent Network Device Naming* to get `eth0`, `eth1`, etc. back
 - `--bbr` Enable TCP BBR congestion control
 - `--power-off` Power off after installation rather than reboot
 - `--architecture <string>` e.g. `amd64`, `i386`, `arm64`, `armhf`, etc.
 - `--boot-partition` Should be used if `/boot` directory is mounted from a dedicated partition like a LVM setup
 - `--firmware` Load additional [non-free firmwares](https://wiki.debian.org/Firmware#Firmware_during_the_installation)
 - `--force-efi-extra-removable` [See](https://wiki.debian.org/UEFI#Force_grub-efi_installation_to_the_removable_media_path). **Useful on Oracle Cloud**
 - `--dry-run` Print generated preseed and GRUB entry without downloading the installer and actually saving them

## Presets

### `china`

 - `--dns '223.5.5.5 223.6.6.6'`
 - `--mirror-protocol https`
 - `--mirror-host mirrors.aliyun.com`
 - `--security-repository mirror`
 - `--ntp ntp.aliyun.com`

### `cloud`

 - `--dns '1.1.1.1 1.0.0.1'`
 - `--mirror-protocol https`
 - `--mirror-host deb.debian.org`
 - `--security-repository mirror`
 - `--ntp 0.debian.pool.ntp.org`