LibraryBridge

Keep Windows game files on their existing drive while putting Proton data on a Linux filesystem. LibraryBridge also finds existing GOG and standalone games and adds them to Lutris.

LibraryBridge runs on Linux. Download the latest release, currently 0.1.0: an AppImage, a portable desktop tarball (no FUSE required), or a command-line tarball. You can also build from source (below).

LibraryBridge is independent and is not affiliated with or endorsed by Valve Corporation. Steam and Proton are trademarks of Valve Corporation.

What it does

Steam libraries

Proton stores a Wine prefix for each game in steamapps/compatdata. Those prefixes need Linux filesystem features that are not reliable on NTFS. The game files can stay on the NTFS drive while their Proton data moves to a Linux filesystem.

LibraryBridge copies and verifies the data, keeps the original as compatdata.backup, and leaves a link where Steam expects it. Your game files do not move, and Steam does not need a configuration change.

Lutris games

LibraryBridge can scan folders for GOG and standalone Windows games that Lutris does not know about. It shows the likely executable for each game so you can review the result before adding it to Lutris. Game files, prefixes, and saves are not moved.

Cover art

Lutris often has no cover art for games it did not download from its own site. LibraryBridge can fetch it from SteamGridDB and put it where Lutris looks for it. Nothing in Lutris's database is changed, and nothing is deleted.

Requirements

• Linux
• Steam for the Steam repair feature
• Lutris for the optional game import feature
• curl and a free SteamGridDB API key for the optional cover art feature
• Rust and Cargo to build from source
• A Linux filesystem with enough free space for the moved Proton data

Installation

Linux downloads

Download the latest release.

Available downloads:

• AppImage desktop build; requires FUSE
• Portable desktop tarball; no FUSE required
• Command-line tarball; no display server required
• Source archive

See the release page for checksums, recovery instructions, SBOM, and third-party notices.

For the AppImage, make it executable and run it:

chmod +x LibraryBridge-0.1.0-x86_64.AppImage
./LibraryBridge-0.1.0-x86_64.AppImage

If your system cannot mount the AppImage, use --appimage-extract-and-run or the desktop tarball instead.

To run the desktop tarball:

tar -xzf librarybridge-desktop-0.1.0-linux-x86_64.tar.gz
./LibraryBridge.AppDir/AppRun

To run the command-line tool:

tar -xzf librarybridge-cli-0.1.0-linux-x86_64.tar.gz
./librarybridge

Arch-based distributions

An Arch PKGBUILD is included in the repository, but an AUR package is not published yet.

Until the AUR package is available, use the Linux downloads above or build from source.

Build from source

git clone https://github.com/amcdev7/LibraryBridge.git
cd LibraryBridge
cargo build --locked --release --workspace

The binaries are created in target/release:

• librarybridge, the command-line tool
• librarybridge-gui, the desktop window

Optional desktop integration

For a source build, this installs the app-menu entry, icons, and links to the release binaries in ~/.local/bin:

packaging/install-desktop.sh

This step is not needed for a packaged release. Packages should install the desktop entry and icons themselves.

Quick start

Close Steam before repairing a library.

List the libraries and find the id to use in the next commands:

./target/release/librarybridge scan

Preview a repair without changing anything:

./target/release/librarybridge fix <id> --dry-run

If the preview looks right, apply it:

./target/release/librarybridge fix <id>

The command asks for confirmation unless you pass --yes. The original Proton data stays beside the library as compatdata.backup.

To move the current data back to the game drive:

./target/release/librarybridge undo <id>

Do not delete the backup by hand. After you have confirmed that the game works, backup can remove it and reclaim the space. This is the only command that deletes data, and it requires recorded evidence that the game launched and saved successfully.

./target/release/librarybridge backup <id>

Choosing where Proton data goes

By default, moved data lives under:

~/.local/share/librarybridge/<library>-<id>/compatdata

To use another Linux filesystem with more space:

./target/release/librarybridge \
  --data-dir /mnt/games/librarybridge \
  fix <id>

The destination can be ext4, btrfs, xfs, or another Linux filesystem that supports the required features. It cannot be exFAT or the same filesystem as the Steam library.

To see how much space the moved data uses:

./target/release/librarybridge storage

Desktop window

./target/release/librarybridge-gui

The window shows library status, explains what needs attention, previews each repair, and runs the same operations as the command-line tool. It also has the Lutris scan and import flow. On the Lutris page, the Cover art panel can automatically download covers for every game that is missing one, and lets you choose the right match by its cover when the automatic match is wrong.

Import games into Lutris

Use this when GOG or standalone Windows games already exist on a drive and you want Lutris to manage them.

Check that Lutris is installed:

./target/release/librarybridge lutris detect

Scan a folder:

./target/release/librarybridge lutris scan \
  --root /run/media/you/Games

The scan reports candidate ids. Review the candidates, then create an import plan and pass it to Lutris:

./target/release/librarybridge lutris plan \
  --root /run/media/you/Games \
  --candidate <id> \
  --output plan.json

./target/release/librarybridge lutris import --plan plan.json

Lutris opens its own installer dialog for each game. Steam games are not imported because Lutris already lists them through its Steam integration.

Cover art for Lutris games

Lutris reads a game's cover from its own coverart directory, named after the game's slug. LibraryBridge fetches missing art from SteamGridDB and puts it there. Nothing in Lutris's database is changed, and nothing is deleted.

Covers are fetched with curl, so it must be installed. A free SteamGridDB API key is required; get one at steamgriddb.com/profile/preferences/api.

Save the key in the desktop window (it is kept for next time), or on the command line:

echo 'YOUR_API_KEY' > ~/.local/share/librarybridge/sgdb-api-key
chmod 600 ~/.local/share/librarybridge/sgdb-api-key

SGDB_API_KEY and --apikey PATH also work. The key is never written anywhere else.

In the desktop window, open Lutris, save the key from Settings if needed, then click Download missing in the Cover art panel. LibraryBridge uses each game's name to choose the best SteamGridDB match and downloads one cover for every Lutris game that does not already have one. Use Find art on an individual game to review preview images and choose a different match.

List what has no cover art. This is offline and needs no key:

./target/release/librarybridge lutris covers --list

Fetch art for every game that has none:

./target/release/librarybridge lutris covers

For one game, or to choose the match yourself:

# Search and list the candidates, with preview links, downloading nothing
./target/release/librarybridge lutris covers --game <slug> --matches

# Use a specific candidate by its id
./target/release/librarybridge lutris covers --game <slug> --match <id>

# Search with different text, or replace art that is already there
./target/release/librarybridge lutris covers --game <slug> --query "Exact Name" --overwrite

The search text defaults to the game's display name. When the automatic choice is wrong, the desktop window's Cover art panel shows the candidates with their covers so you can pick the right one. Restart Lutris to see new covers.

Safety and recovery

• scan, storage, and --dry-run do not change files.
• A repair copies and verifies the data before changing the Steam library.
• A repair keeps the original. It does not delete it.
• undo copies the current data back, including saves made after the repair.
• backup is the only command that deletes anything. It checks the moved copy and requires evidence that the game launched and saved successfully.
• An interrupted repair can be reviewed again. Unfinished data is kept rather than deleted automatically.
• lutris covers writes one image file into Lutris's own coverart directory. It changes nothing else, and it never deletes a cover.

Limitations

• Linux only
• exFAT libraries are detected but are not repaired automatically
• Timestamps, hard-link relationships, and sparse-file allocation are not preserved by the copy
• A successful repair fixes the location of Proton data. It does not guarantee that a particular game will run
• Cover art needs network access and a SteamGridDB API key, and the automatic match can choose the wrong game; pick the right one from the window, or with --match

Troubleshooting

Run a fresh scan first. Include the LibraryBridge version, Linux distribution and kernel, filesystem and mount driver, Steam installation type, and redacted command output when opening an issue. Use GitHub Discussions for questions, ideas, and general feedback.

Do not attach saves, Proton prefixes, registry files, or Steam account data.

For contributors

cargo test --locked --workspace
cargo clippy --locked --workspace --all-targets -- -D warnings
cargo build --locked --release --workspace

The GUI has deterministic preview data for visual checks:

cargo run -p librarybridge-gui -- --preview --screen home

License

LibraryBridge is available under the MIT License. See LICENSE.