GTNH Prism Launcher Updater

A bash script to safely update GT New Horizons client instances in Prism Launcher, following the official update instructions.

Features

• Clones your existing instance (preserves the original)
• Replaces config, mods, and serverutilities folders automatically
• Handles Java 17+ files (libraries, patches, mmc-pack.json)
• Auto-detects Prism Launcher instances folder
• Dry-run mode to preview changes before applying
• Non-interactive mode for automation
• Supports .zip, .tar.gz, and .tar archives

Requirements

• Bash 4.0+ (Git Bash on Windows)
• tar or unzip (depending on archive format)
• curl or wget (only if downloading from URL)

Usage

./update.sh [OPTIONS]

Options

Option	Description
-i, --instance DIR	Path to your current GTNH instance folder (required)
-n, --name NAME	Name for the new/updated instance (required)
-u, --url URL	Download URL for the new client version
-f, --file FILE	Path to already downloaded client archive
-p, --prism-dir DIR	Prism instances folder (auto-detected if not set)
-j, --java17	Using Java 17+ (also replaces libraries, patches, mmc-pack.json)
--dry-run	Simulate the update without making changes
-y, --yes	Skip confirmation prompt
-h, --help	Show help message

Examples

Update from a downloaded archive:

./update.sh -i ~/.local/share/PrismLauncher/instances/GTNH_2.8.1 \
    -n "GTNH 2.8.4" \
    -f ~/Downloads/GT_New_Horizons_2.8.4_Client.zip

Update with Java 17+ and skip confirmation:

./update.sh -i /path/to/GTNH_instance -n "GTNH 2.8.4" -f client.zip --java17 --yes

Download and update in one step:

./update.sh -i /path/to/GTNH_instance -n "GTNH 2.8.4" \
    -u "https://example.com/gtnh-client.zip" --java17

Preview what would happen (dry-run):

./update.sh -i /path/to/instance -n "GTNH New" -f client.zip --dry-run

Custom Prism instances folder (e.g., Windows with custom path):

./update.sh -i "D:/PrismInstances/GTNH_2.8.1" \
    -n "GTNH 2.8.4" \
    -f client.zip \
    -p "D:/PrismInstances"

What It Does

1. Downloads the new client version (if URL provided)
2. Clones your existing instance to a new folder
3. Removes old folders: config, mods, serverutilities (and scripts, resources if present)
4. Removes Java 17+ files if --java17 flag is set
5. Extracts new client files from the archive
6. Installs new folders to the cloned instance
7. Installs Java 17+ files if --java17 flag is set
8. Updates instance name in configuration

Prism Launcher Instance Locations

The script auto-detects these standard locations:

OS	Path
Linux	~/.local/share/PrismLauncher/instances/
Linux (Flatpak)	~/.var/app/org.prismlauncher.PrismLauncher/data/PrismLauncher/instances/
macOS	~/Library/Application Support/PrismLauncher/instances/
Windows	%APPDATA%/PrismLauncher/instances/
Windows (Scoop)	%HOMEPATH%/scoop/persist/prismlauncher/instances/

If you have a custom location, use --prism-dir to specify it.

After Updating

1. Launch Prism Launcher - The new instance should appear
2. Review settings - Check Java arguments if using Java 17+
3. Test the instance - Launch and verify everything works

For Java 17+ setup, see: https://github.com/GTNewHorizons/lwjgl3ify

Running Tests

bash update_test.sh

License

MIT License - see LICENSE for details.

Contributing

Contributions are welcome! Please feel free to submit issues or pull requests.

See Also

• gtnh-server-updater - Server-side update script