Configuration & files¶
Everything Prefixr stores, the command-line options it understands, and what a game launch sets up.
Prefixr's app ID is com.tristan.prefixr, so its folders follow the XDG base directories under that
name.
- Configuration file
- Data
- Elsewhere on your system
- Command-line options
- API keys
- What a launch sets up
- Backing up and resetting
Configuration file¶
~/.config/com.tristan.prefixr/config.json holds the library and all settings: the games, the prefix
list, the global Performance, Graphics, Overlay and Proton settings, the SteamGridDB API key and the
GitHub token.
Prefixr saves it atomically (written to a temporary file, then renamed), so a crash or a full disk never leaves half a file. If the file can't be read when Prefixr starts, Prefixr shows the error and quits without touching it, rather than starting empty and overwriting your library on the next save. Fix the JSON or move the file away to start fresh.
The runners folder is the one setting without a UI: runners_dir in config.json. Quit Prefixr
before editing the file.
Data¶
~/.local/share/com.tristan.prefixr/ holds everything Prefixr downloads or generates:
| Path | Contents |
|---|---|
runners/ |
Downloaded runners, one folder each. Any Proton or Wine build you put or symlink here is listed too. |
umu-launcher/ |
Prefixr's own copy of umu-launcher, with its version. |
directx-layers/ |
DXVK and VKD3D-Proton for Wine runners, with their versions, and the cached wine-mono installers. |
winetricks/ |
The winetricks script, refreshed weekly. |
artwork/ |
Images chosen from SteamGridDB, named after the game's ID, and the covers of store games (store-epic-<app>.jpg, store-gog-<id>.jpg, store-amazon-<id>.jpg). |
helpers/ |
The store tools (Legendary, gogdl, Nile), one file per pinned version. Removed when you disconnect the store. |
stores/epic/ |
Legendary's own config (legendary/, including your Epic login) and the cached game list (library.json). |
stores/gog/ |
gogdl's login and manifests (gogdl/), your account name (account.json), the cached game list (library.json) and GOG's shared redistributables (redist/). |
stores/amazon/ |
Nile's config (nile-config/nile/: your Amazon login, the game list, the installed games and their manifests, the Amazon Games SDK) and the cached game list (library.json). |
prefixes/ |
The prefixes created for store games, one per game (epic-<app>, gog-<id>, amazon-<id>). |
exe-icons/ |
Icons extracted from the games' .exe files. |
mangohud/, vkbasalt/ |
The MangoHud and vkBasalt config of each game, written on every launch. |
logs/<game-id>/ |
The last 10 launch logs of each game. |
logs/prefixes/<prefix>/ |
The last 10 logs of setup programs, winetricks and Wine tools run in a prefix. |
logs/stores/<store>/<app>/ |
The last 10 install logs of each store game. |
shortcut-icons/ |
The icon of the Install Prefixr file-manager entry. |
WebKitCache/, storage/, localstorage/ |
The window's own browser data (see Troubleshooting). |
~/.cache/com.tristan.prefixr/umu-database.json caches the umu database for the protonfixes search
for a day.
Your prefixes live wherever you created or found them; Prefixr only remembers their paths.
Elsewhere on your system¶
| Path | Written when |
|---|---|
~/.local/share/umu/ |
umu-launcher downloads the Steam Linux Runtime there, shared with other umu-based launchers. Follows UMU_FOLDERS_PATH and XDG_DATA_HOME as umu does. |
~/.local/share/applications/com.tristan.prefixr.install.desktop |
On every start, to register Install Prefixr in your file manager's Open With menu for .exe files. Hidden from the app menu. |
~/.local/share/applications/<game>-<id>.desktop |
To start menu on a game. |
| Your desktop folder | To desktop on a game. Prefixr honors a localized XDG_DESKTOP_DIR, such as ~/Schreibtisch. |
~/.steam/root/userdata/<user>/config/shortcuts.vdf and grid/ |
Add to Steam, Update in Steam and Remove from Steam. The previous file is kept as shortcuts.vdf.bak. |
$XDG_RUNTIME_DIR/prefixr/<game-id>.lock |
While a game launches or runs, so two Prefixr processes (an open window and one Steam started) never start the same game twice. |
/etc/sysctl.d/99-prefixr-max-map-count.conf |
Only when you click Increase now for vm.max_map_count, after a password prompt. |
Command-line options¶
| Option | Effect |
|---|---|
prefixr --launch <game-id> |
Starts the game. If Prefixr is already open, that window starts it instead. Desktop and menu shortcuts use this. |
prefixr --run <game-id> |
Starts the game without any window and exits when the game does. A failure before the game starts is shown in a dialog. Steam uses this for games added to it. |
prefixr --install <path/to/setup.exe> |
Opens the install dialog for that setup program. The Install Prefixr file-manager entry uses this. |
prefixr game …, prefix …, runner …, umu … |
The command line: everything the window does, from a terminal or a script. See Command line & AI agents. |
A game's ID is the id of its entry in config.json. It also appears in the Exec= line of the
game's shortcuts.
API keys¶
Both are optional and stored in config.json.
| Key | Where to enter it | What it's for |
|---|---|---|
| SteamGridDB API key | SteamGridDB page | Searching artwork, and finding a game's Steam app ID for the protonfixes match |
| GitHub personal access token, no scopes | Runners page, GitHub section | Raising GitHub's API limit from 60 to 5000 requests per hour for runner, umu and DXVK downloads |
What a launch sets up¶
For reference when reading a game's log or reproducing a launch by hand.
The command, from the outside in, each part only when it's enabled and available:
gamescope [-w W] [-h H] [-r FPS] [-f] [--mangoapp] --systemd-inhibit --what=idle:sleep --, for Prevent sleeppowerprofilesctl launch --profile performance, for the performance power profileumu-runfor a Proton runner, or the runner'swinefor a Wine runner- the game's
.exeand its launch arguments
The environment:
| Variable | Set to |
|---|---|
WINEPREFIX |
The game's prefix |
WINEDLLOVERRIDES |
Always winemenubuilder.exe=, so Wine doesn't add menu entries and file associations for what runs in the prefix. For a Wine runner also the DXVK and VKD3D-Proton DLLs as native-then-builtin. |
PROTONPATH |
The Proton runner (Proton only) |
GAMEID, STORE |
The game's protonfixes match (Proton only) |
PROTON_* |
The Proton switches set to On (1) or Off (0) |
WINEDEBUG |
-all for a Wine runner, which keeps Wine's debug output from slowing games down |
MANGOHUD, MANGOHUD_CONFIGFILE |
With the overlay enabled |
ENABLE_VKBASALT, VKBASALT_CONFIG_FILE |
With vkBasalt enabled |
LD_PRELOAD |
libgamemodeauto.so.0 with GameMode. An LD_PRELOAD Prefixr itself was started with (such as Steam's overlay) is kept. |
With Gamescope, the MangoHud and vkBasalt variables only go to the game inside it, so they don't apply to Gamescope's own output a second time.
The game's own environment variables come last and win, except WINEDLLOVERRIDES and LD_PRELOAD,
which are appended to.
Before a Proton game's first launch, Prefixr creates the prefix with umu's createprefix so the
download of the Steam Runtime shows as Starting…. Before a Wine game's first launch, it runs
wineboot, installs the wine-mono version that Wine build expects, and links in DXVK and
VKD3D-Proton.
Backing up and resetting¶
- To back up your library, copy
~/.config/com.tristan.prefixr/config.json. With~/.local/share/com.tristan.prefixr/artwork/, your chosen artwork comes along too. Save games live in the prefixes, so back those up separately. - To start over, quit Prefixr and remove
~/.config/com.tristan.prefixr/. To free the space runners and caches take, also remove~/.local/share/com.tristan.prefixr/. Neither touches your prefixes or games.