An easy to use modlist installer for Minecraft Java Edition. Think of this as an open source alternative to the Twitch Launcher.

Usage for users

Usage is as simple as downloading the latest release for your operating system to a modpack directory and then running the executable. The installer will ask you to specify a modlist URL: just copy and paste a link to a modlist. For reference, after running the installer your directory structure will look something like:

./
├── config/
├── main.modlist
├── mcmli.exe
└── mods/

On macOS and Linux, you may have to set execute permissions for the file before running:

cd /path/to/your/modpack/directory
chmod u+x mcmli

Now you can run the binary either by double clicking it, or in the CLI.

Usage for authors

The installer reads modlists from all files with the .modlist extension in alphabetical order. Typical use should only require one modlist which could be called something like main.modlist or <modpack-name>.modlist.

Modlist format

Perhaps the easiest way to understand the modlist format is to see an example:

<Update>
# Modlists can self update by using <Update> as the first
# control directive.
https://url/to/this/modlist

[mods]
# This line is a comment and will be ignored.
https://somesite/commonmod.jar # Comments after URLs must be preceeded by whitespace.
<Client-Only>
https://somesite/client-only-mod.jar
<Server-Only>
https://somesite/server-only-mod.jar

# Here we ask the user to download a file called 'OptiFine_1.12.2_HD_U_F5.jar'
# from the URL 'https://optifine.net/adloadx?f=OptiFine_1.12.2_HD_U_F5.jar'.
# Once they download it, the mod will be moved to the cache and then linked to the
# modpack directory.
[mods] <User-Download>
https://optifine.net/adloadx?f=OptiFine_1.12.2_HD_U_F5.jar {OptiFine_1.12.2_HD_U_F5.jar}

[config] <Always-Fetch>
https://somesite/commonconfig.cfg

We refer to text inside square [] or angle <> brackets as control directives. Control directives may occur on lines by themselves or on the same line as other control directives. Text inside [] brackets specifies the directory (relative to the executable) in which to download the following URLs. Text inside <> brackets specify options for the current 'context' (until the next set of [] brackets). Valid options are:

• <Update> Always download these files to the current directory and then resolve the modlist as usual.
• <Always-Fetch> Always download these files regardless of whether or not they are present already.
• <Smart-Fetch> Only download these files if they do not exist (default behaviour).
• <Server-Only> Only download these files if the current instance is a server.
• <Client-Only> Only download these files if the current instance is a client.
• <Common> Download these files for both servers and clients (default).
• User-Download Prompt the user to download a file from the URL given. See above for an example.