steam-add-nonsteam-game adds local applications to the currently running Steam client's library from the command line. Steam updates the library immediately; the script does not edit shortcuts.vdf and Steam does not need to restart.

The script accepts:

• Linux .desktop launchers
• Native executables and executable shell scripts
• AppImages
• Windows .exe files
• Literal launch targets and application URIs such as lutris:rungameid/220

• Steam for Linux
• Python 3.10 or newer

No third-party Python packages are required.

install -Dm755 steam-add-nonsteam-game \
  ~/.local/bin/steam-add-nonsteam-game

Ensure ~/.local/bin is in your PATH, then keep Steam running while using the command.

Add a desktop launcher:

steam-add-nonsteam-game \
  ~/.local/share/applications/proton-selector.desktop

Add an executable or AppImage:

steam-add-nonsteam-game ~/Applications/MyGame.AppImage

Add a literal application URI:

steam-add-nonsteam-game 'lutris:rungameid/220'

If a supplied target exists on disk, the script resolves and validates it as a file. If it does not exist, the text is preserved instead of being rejected. For URI targets, the generated launcher invokes the registered scheme command. For example, the Lutris target above becomes:

Exec="lutris" "lutris:rungameid/220"

Steam imports the URI as the launch argument rather than mistaking it for a filesystem path.

Set a custom Steam title:

steam-add-nonsteam-game --name "Proton Plus" "$(which protonplus)"

-n, --name, and --title are equivalent. A custom title can only be used with one path at a time.

Add several programs at once:

steam-add-nonsteam-game app-one.desktop app-two.desktop ~/bin/my-game

Preview a request without changing the Steam library:

steam-add-nonsteam-game --dry-run /path/to/program

The command refuses to add an exact path already present in any local Steam user's shortcuts.vdf. To intentionally create a duplicate:

steam-add-nonsteam-game --allow-duplicate /path/to/program

The running client exposes the URL handler steam://addnonsteamgame/<encoded-path>. The script validates and resolves the supplied path, creates Steam's /tmp/addnonsteamgamefile sentinel, and passes the encoded URL to the steam launcher. Steam assigns the shortcut's AppID and writes its own configuration safely.

When --name or a literal target is used, the script creates a persistent launcher under ~/.local/share/applications/steam-add-nonsteam-game/. Its Name is the requested Steam title and its Exec points to the original program. This is necessary because Steam's add URL accepts a path but has no title parameter.

Some SteamOS-derived distributions already ship a more limited shell helper named steamos-add-to-steam that uses the same mechanism.