Install lsyncd with Homebrew

Project links

• Homepage

Commands and aliases

• lsyncd

Project history

The official README and manual describe Lsyncd as a lightweight live mirror solution built around platform filesystem event APIs: inotify on Linux and fsevents on macOS. Instead of introducing a new filesystem or block replication layer, it waits briefly, collapses change events, and spawns rsync or related actions to keep a target tree synchronized.

Lsyncd's configuration model is a major part of its identity. The manual documents Lua-syntax configuration files, daemon-wide `settings`, default sync layers such as `default.rsync`, `default.rsyncssh`, and `default.direct`, and lower-level customization paths that can range from shell commands to Lua code.

Adoption history

The project has unusually strong adoption signals for a daemon-sized Unix utility: GitHub shows roughly 6.1k stars, 474 forks, 926 commits, and a long issue history. The supplied package-manager facts show packaging across Homebrew, Debian, Ubuntu, Fedora/DNF, Alpine, Nix, and openSUSE/Zypper, which is consistent with a tool used by administrators rather than a single-platform script.

Recent official release notes show renewed maintenance. Version 2.3.0 is described as the first release 'since quite a while' under a new maintainer, adding nix flake support, tunnel commands, `batchSizeLimit`, `-onepass`, crontab support, and relative executable paths; version 2.3.1 followed with bug fixes and cleanup.

How it is used

The official invocation docs say Lsyncd can be configured mainly by passing a config file as the only command-line option, or cursorily through options such as `-rsync` and `-rsyncssh`. The manual's examples show typical one-way mirroring from a source directory to a local destination, remote rsync target, or remote host and target directory.

The project explicitly warns against treating it as a two-way synchronization system. Its README frames Lsyncd as best for slowly changing local directory trees, especially one-way sync from a secure area to a less secure mirror, and points users at specialized tools such as git-annex for bidirectional or conflict-aware workflows.

Why package nerds care

Lsyncd is package-nerd significant because it sits at the intersection of classic Unix tools: kernel file notifications, rsync, ssh, daemonization, and Lua configuration. It is the kind of package administrators install to avoid a heavier distributed filesystem while still getting near-real-time mirroring from familiar components.

Its cross-distro packaging also makes it useful as a history marker: it is not a fashionable single-ecosystem tool, but a durable sysadmin daemon that earned its place in major package sets through practical deployment value.

Timeline

• 2.1 era: Documentation says Lsyncd is predominantly configured through a config file.
• 2.2.1: README states Lsyncd requires rsync >= 3.1 on source and target machines.
• 2.3.0: Release notes describe renewed maintenance and new features including nix flakes, tunnels, `-onepass`, and crontab support.
• 2.3.1: Latest GitHub release lists bug fixes and code cleanup.

Related projects

• rsync is the default synchronization backend.
• ssh is used by the rsync+ssh mode to handle remote moves efficiently.
• Lua supplies the configuration language.
• DRBD, GlusterFS, BindFS, Mirror, and git-annex are discussed in the README as related synchronization approaches with different trade-offs.

Sources

• https://github.com/lsyncd/lsyncd
• https://github.com/lsyncd/lsyncd/releases
• https://lsyncd.github.io/lsyncd/
• https://lsyncd.github.io/lsyncd/manual/config/file/
• https://lsyncd.github.io/lsyncd/manual/invoking/
• source_facts.package-manager