Pacman Backup

This is somewhat a release blog entry about Pacman Backup. This article somewhat documents the usage scenarios and why I've decided to refactor an older implementation.

A couple weeks ago someone from Cuba contacted me and told me about problems and issues with the old version of the tool, and I finally got the time to refactor it and fix the outstanding bugs and limitations. As it turns out, Cuba's Sneakernet uses pacman-backup to share and install ArchLinux on their machines, which is kind of awesome to hear about.

screenshot

Pacman Backup

GitHub Repository and GitLab Mirror

Pacman-Backup is a CLI tool that allows to download available packages on one machine, and to transfer the packages via USB drives or via a locally running pacman mirror server to another machine that's airgapped and doesn't have direct access to the internet.

The old version (written in nodejs ) of Pacman Backup had some bugs and limits in what it could do, the new version (rewritten in go ) provides much tighter integration with pacman 's configuration files that resolves those issues.

The new version was rewritten in go so that it has no dependencies and doesn't rely on having to have the same system with the same glibc dependent library versions installed. This way the tool itself can also be shared in a portable manner via USB drives, and doesn't need to be recompiled and neither to be redownload or reinstalled.

How it works

The rewrite of pacman-bacup generates a temporary /tmp/pacman-backup.conf file that can be used by pacman with the --config flag. This way it guarantees interoperability with update constraints, like HoldPkg (stickied packages) or IgnorePkg (ignored packages) options in the local /etc/pacman.conf file.

The temporary config file changes essentially the DBPath and CacheDir options and points those to the mounted target folder on the USB drive.

Pacman-backup also parses pacman's output of -Si , -Qi , and -Qip to find out what packages need to be downloaded and what packages are available already in the local package cache.

Another optimization that pacman-backup offers is pacman-backup cleanup , which allows to manage the limited memory on a USB drive in a better way. The cleanup action preserves only the latest version of each package, while also respecting to keep stickied or ignored packages.

Usage Examples

Pacman Updates via USB Drive

On the machine with internet connection, do the following :

  1. Insert and mount the USB drive.
  2. Download the packages to the USB drive.
  3. Cleanup the package cache on the USB drive.
pacman-backup download /run/media/$USER/usb-drive;
pacman-backup cleanup /run/media/$USER/usb-drive;
sync;

On the machine without internet connection, do the following :

  1. Insert and mount the USB drive.
  2. Upgrade packages from the cache on the USB drive.
sudo pacman-backup upgrade /run/media/$USER/usb-drive;

Pacman Updates via Meshnet LAN or Wi-Fi

On the machine with internet connection, do the following :

  1. Download all updateable packages.
  2. Serve a local pacman mirror server.
sudo pacman-backup download;
pacman-backup serve;

On the machine without internet connection, do the following :

  1. Download updates from the local pacman mirror server.
  2. Upgrade packages from the cache on the local hard drive.
sudo pacman-backup download http://192.168.0.10:15678/;
sudo pacman-backup upgrade;

Downloads

If you have a censored internet connection and cannot access GitHub or GitLab , you can also try to use the known mirrors of my website and/or the direct downloads here : Download source of pacman-backup

You'll need go version 1.23 or later to build pacman-backup , the project has zero dependencies.

The old node.js version can be downloaded in the Projects Overview .