I made SimpleSync, a tiny open-source folder sync / copy tool in C (single exe, Windows/macOS/Linux)

[u/SailHighSea]

Hi all, I’ve been building a small tool called SailHighSea SimpleSync and just put the first pre-release up on GitHub. I’d love feedback, especially from people who copy lots of files or use USB drives and NAS shares.

What it is

A one-way folder sync and fast copy tool. It’s one small file: no installer, no runtime, portable. It’s written in C11 with raylib, MIT licensed.

Two modes

Sync tasks: pick a source and a target, and new or changed files get copied. You can run it by hand or turn on auto-sync (it watches the folder and syncs after changes stop). Optional mirror mode removes files from the target that are gone from the source.

Quick Copy: a one-off copy that is never saved, with a copy-manager style panel (pause / skip / stop, verify, file list, speed graph, log). You can drop more files or folders onto it while it runs. If a file already exists you get an overwrite dialog: overwrite, skip, keep both, or a rule for all files (older, smaller, different size, rename...).

Under the hood

Multi-threaded copying with read-ahead for small files (fewer seeks on hard disks)

Large files are read while the previous block is written

Removable drives get one writer and direct writes, since parallel writes hurt USB sticks

Optional verify: read back and compare a 64-bit hash

Light/dark/system theme, tray icon and start with Windows (Windows only for now)

Idle it uses almost no CPU, and it shrinks its memory use after a few seconds without input

Honest status

It’s early (v0.0.x). The Windows build gets nearly all my testing. The Linux and macOS builds compile in CI, but I’ve barely run them on real machines. A native Windows ARM64 build is also in CI, marked experimental. All builds are unsigned, so SmartScreen and Gatekeeper will warn.

On speed: on my Photoshop folder copy to a USB stick, an early build was a bit slower than TeraCopy (about 6 min vs 4m50s). I’ve since changed how it handles USB drives, but I haven’t re-timed it yet, so I’m not claiming to beat anything. Benchmarks on your own drives would be very welcome.

Mirror mode deletes files in the target permanently, so please try it on test copies first.

Download (Windows / Linux / macOS / Windows ARM64): https://github.com/SailHighSea/sailhighsea-ss/releases
Source, README and screenshot: https://github.com/SailHighSea/sailhighsea-ss
Bug reports, ideas and “it crashed on my distro” reports are all useful. Issues are open on the repo.

[u/Minimum_Hour519]

Interesting I built diskpush.com which is rsync with a fikkezilla type interface