Windows installation script from Aalto "Rsync on Windows" page fails due to outdated package URLs and zstd extraction method

[RixRomeo]

Description:

Hi 👋

I’ve been following the installation instructions from the official Aalto Scientific Computing page:
👉 https://scicomp.aalto.fi/scicomp/rsynconwindows/

When running the provided installRsync script on Windows 11 (Git Bash), the installation fails during the package extraction phase with errors like:

zstd: /*stdin*: unsupported format
tar: Child returned status 1
tar: Error is not recoverable: exiting now

or sometimes:

zstd: libzstd.tar.zst: unsupported format
tar: This does not look like a tar archive
tar: Exiting with failure status due to previous errors

---

Root cause

After debugging the script, I found two main issues:

1. The script downloads outdated packages from repo.msys2.org which no longer exist — e.g.
   libzstd-1.5.2-2-x86_64.pkg.tar.zst now returns an HTML 404 page, not a valid .zst file.
2. The command tar -I zstd -xvf is not portable under Git Bash / MinGW on Windows — it doesn’t properly pass the -d flag to zstd, leading to the “unsupported format” errors.

---

Proposed fix

Below is a working version of the script, successfully tested on Windows 11 (Git Bash).
It uses up-to-date MSYS2 mirrors, a safer extraction method (zstd -d -c | tar -xv), and includes simple integrity checks.

#!/usr/bin/env bash
set -euo pipefail

BASE_URL="https://mirror.msys2.org/msys/x86_64"

PKG_RSYNC="rsync-3.4.1-1-x86_64.pkg.tar.zst"
PKG_ZSTD="libzstd-1.5.7-1-x86_64.pkg.tar.zst"
PKG_XXHASH="libxxhash-0.8.3-1-x86_64.pkg.tar.zst"
PKG_OPENSSL="libopenssl-3.6.0-1-x86_64.pkg.tar.zst"

ZSTD_ZIP_URL="https://github.com/facebook/zstd/releases/download/v1.5.0/zstd-v1.5.0-win64.zip"

say() { printf "\n==> %s\n" "$*" >&2; }
die() { echo "ERROR: $*" >&2; exit 1; }
need_cmd() { command -v "$1" >/dev/null 2>&1 || die "Missing command: $1"; }
download() { curl -fL --retry 3 --retry-delay 1 -o "$2" "$1" || die "Failed to download: $1"; }

cd || die "Failed to enter home directory"
mkdir -p "$HOME/bin" "$HOME/lib"

rm -rf "$HOME/tempinstall"
mkdir -p "$HOME/tempinstall"
cd "$HOME/tempinstall"

say "Downloading zstd"
download "$ZSTD_ZIP_URL" "zstd.zip"
unzip -q zstd.zip
cp -r zstd-v1.5.0-win64/* "$HOME/bin/"
rm -rf zstd.zip zstd-v1.5.0-win64

ZSTD="$HOME/bin/zstd.exe"
[ -x "$ZSTD" ] || die "zstd.exe not found"

say "Downloading packages"
download "$BASE_URL/$PKG_RSYNC"   "rsync.tar.zst"
download "$BASE_URL/$PKG_ZSTD"    "libzstd.tar.zst"
download "$BASE_URL/$PKG_XXHASH"  "libxxhash.tar.zst"
download "$BASE_URL/$PKG_OPENSSL" "libopenssl.tar.zst"

say "Extracting packages"
"$ZSTD" -d -c rsync.tar.zst     | tar -xv
"$ZSTD" -d -c libzstd.tar.zst   | tar -xv
"$ZSTD" -d -c libxxhash.tar.zst | tar -xv
"$ZSTD" -d -c libopenssl.tar.zst| tar -xv

say "Installing"
cp -r usr/bin/* "$HOME/bin/" || true
cp -r usr/lib/* "$HOME/lib/" || true
cd ..
rm -rf "$HOME/tempinstall"

say "Installation complete. Run 'rsync --version' in a new Git Bash window."

---

Why this works

✅ Uses https://mirror.msys2.org instead of the outdated repo.msys2.org.
✅ Ensures .zst files are actually valid (not HTML).
✅ Uses zstd -d -c | tar -xv for reliable decompression in Git Bash.
✅ Installs locally in ~/bin and ~/lib, no admin rights needed.
✅ Tested successfully on Windows 11, Git Bash

---

Environment

• OS: Windows 11
• Shell: Git Bash
• Architecture: x86_64
• Tested in: clean user environment, no MSYS2 preinstalled

---

Summary

The script on the Aalto “Rsync on Windows” page currently breaks due to outdated packages and extraction issues under Git Bash.
The proposed fix above works reliably and could replace the current version in the documentation.

Would you consider updating the script on the page (or the referenced repository) accordingly?
It would make the setup process much smoother for Windows 11 users.

Thanks a lot for your work and documentation — it’s been really helpful! 🙌