pacsync

Update all sync databases

$ sudo pacsync

$ sudo pacsync [repository1 repository2 ...]

$ sudo pacsync --force

$ sudo pacsync --config [path/to/pacman.conf]

$ sudo pacsync --updated

pacsync [options] [target_repository]

-h, --help
    Display a help message and exit, showing available options and usage.

-v, --verbose
    Enable verbose output, providing more detailed information about the synchronization process, including files being transferred.

-d, --dry-run
    Perform a trial run without making any actual changes to the local mirror. It simulates the synchronization and shows what files would be transferred or deleted.

-q, --quiet
    Suppress most output during the synchronization process, only showing critical errors or minimal status updates.

-r <name>, --repo <name>
    Specify a particular repository (e.g., core, extra, community) to synchronize instead of all configured repositories.

-c <path>, --config <path>
    Specify an alternate configuration file for pacsync. This allows for different synchronization setups without modifying the default configuration.

-f, --force
    Force synchronization even if the remote repository appears to be identical to the local mirror, ensuring all files are checked and potentially re-downloaded.

-l, --list-repos
    List all configured repositories without initiating any synchronization process.

pacsync is a utility, typically implemented as a shell script, designed to synchronize a local Arch Linux mirror server with official Arch Linux repositories. Its primary purpose is to ensure that all local package databases and package files are kept up-to-date, providing users who point to the local mirror with the latest software. Unlike pacman, which manages packages on an end-user system, pacsync operates at the mirror level, downloading and managing the repository data itself.

The utility often leverages rsync(1) to efficiently transfer only the changed or new files from the upstream source to the local mirror directory. This includes `.pkg.tar.zst` package files, their corresponding `.sig` signature files, and crucial database files like `core.db`, `extra.db`, etc., for each repository. By automating this process, pacsync plays a critical role in maintaining the integrity and freshness of the Arch Linux mirror network, which is essential for providing reliable and fast updates to Arch Linux users worldwide.

pacsync is typically a community-developed script or utility, not an official part of the pacman package manager itself. Its exact behavior and available options can vary significantly between implementations.

Maintaining an Arch Linux mirror using pacsync requires substantial disk space and network bandwidth, as the full repositories can be hundreds of gigabytes in size. Improper configuration can lead to an outdated, inconsistent, or even corrupt mirror, which can negatively impact users relying on it. It often requires root privileges to write to the designated mirror directories and should be configured carefully, often scheduled via cron(8).

pacsync typically relies on a configuration file (e.g., `/etc/pacsync.conf`, `/etc/mirror-sync.conf`, or an internal script configuration) to define its operational parameters. This file usually specifies the upstream mirror sources (e.g., `rsync://mirror.archlinux.org/archlinux/`), the local destination directory for the mirror, which specific repositories to synchronize, and any custom `rsync` options or filters. Proper configuration is paramount to ensure the mirror functions correctly and efficiently.

The primary dependency for most pacsync implementations is rsync(1), which is the underlying tool used to perform the actual file transfers between the upstream source and the local mirror. Depending on the script's features, it might also rely on standard shell utilities, `curl(1)` or `wget(1)` for fetching auxiliary files or checking connectivity, and `find(1)` or `xargs(1)` for directory manipulation. Adequate disk space and a reliable internet connection are also critical operational 'dependencies'.

The need for efficient Arch Linux mirror synchronization tools arose early in Arch Linux's history as its user base grew. Initially, mirror operators would often use manual `rsync` commands or simple scripts to keep their mirrors updated. Over time, more sophisticated scripts, often given names like `pacsync`, `mirror-sync`, or `pacman-sync`, emerged to automate and streamline this process.

These utilities standardized common tasks such as fetching repository lists, synchronizing multiple repositories (core, extra, community, etc.), handling database updates, and managing temporary files. While there isn't a single official `pacsync` command universally distributed with Arch Linux, the concept and various implementations by mirror operators and the wider Arch Linux community have been crucial in maintaining the robustness and availability of the Arch Linux package ecosystem.

pacman(8), rsync(1), cron(8), curl(1)