Linux

Developing and playing on a Linux desktop, from the same clone. Every launcher has a .sh twin beside its .bat, with the same name, the same description line and the same behaviour; each one sources launchers/_shared/common.sh, which resolves the Configuration and locates the engine. A launcher that only works on Windows (the windows/ exports, the ServUO shard, the plugin probe, side by side) still has its .sh, which says why and exits 2.

Settings are written in launchers/_shared/config.local.sh (yours, gitignored, from config.local.sh.example) over the defaults in config.sh: the twins of config.local.bat and config.bat, with the same keys, in the same order (environment, config.local.sh, config.sh). common.sh sources them, then tools/shellenv adds the derived paths through tools/guo/config.py, which reads the same two files on Linux. A machine that only has a config.local.bat keeps it: it is read when there is no config.local.sh.

The Steam Deck page is a different job: it exports a standalone build and pushes it to a Deck over ssh.

Requirements

Linux	x86_64 (arm64 should work; untested). Checked on Linux Mint 22 (Ubuntu 24.04 base), X11.
Godot	4.7.2 stable, mono/.NET, mono_linux_x86_64. launchers/dev/fetch_godot.sh fetches it into tools/godot.
.NET SDK	10.0. The project's C# uses C# 14 features (the field keyword, first-class spans), so an 8.0 or 9.0 SDK fails the build even though the client targets net8.0. The 8.0 runtime must be installed beside it, because the client runs on net8.0.
Python	3.12 or newer, as python3.
Tools	git, curl, unzip. xvfb-run for scripted runs that should not open a window on your desktop.
A UO client install	The Windows install works as it is, including one inside a Wine prefix.

A per-user .NET with no root, if the distribution's packages are older:

curl -sSL https://dot.net/v1/dotnet-install.sh -o dotnet-install.sh
bash dotnet-install.sh --channel 10.0 --install-dir ~/.dotnet
bash dotnet-install.sh --channel 8.0 --runtime dotnet --install-dir ~/.dotnet
export DOTNET_ROOT=~/.dotnet PATH=~/.dotnet:$PATH

common.sh uses ~/.dotnet by itself when no dotnet is on PATH.

From a fresh clone

cp launchers/_shared/config.local.sh.example launchers/_shared/config.local.sh
# set UO_CLIENT_DATA (and UO_CLIENT_VERSION) in it
launchers/pipeline/00_bootstrap.sh       # engine, upstream reference, data check
launchers/dev/smoke.sh                   # the seven-step health check
launchers/game/play.sh                   # run it

A UO install in a Wine prefix is typically at ~/.wine/drive_c/Program Files (x86)/Electronic Arts/Ultima Online Classic. Set UO_CLIENT_VERSION to that client's version: the dev shard reads it from the same install and kicks an older version than the one it finds.

The dev shard

launchers/shard/fetch.sh       # clone ModernUO + apply tools/modernuo/patches
launchers/shard/build.sh       # publish release linux x64
launchers/shard/run.sh         # run it (Ctrl-C to stop)
launchers/shard/populate.sh    # generate the world (once)

ModernUO publishes a native ModernUO apphost on Linux; tools/editor_shard uses it for the editor's private instance as well.

Where things go

Cache (UO_CACHE_DIR)	~/.local/share/GUO/cache ($XDG_DATA_HOME if set)
Client home: profiles, journal logs, screenshots	~/.local/share/GUO, the cache's parent, as on Windows

What is checked

On Linux Mint 22 with a 7.0.114.2 install in a Wine prefix: smoke.sh passes all six steps, the editor smoke passes all eighteen checks, the dev shard builds, boots headless and is populated from the client, and the input probe logs in, walks the world, opens gumps and gets speech back from the shard.

Not yet checked: audio on a real output device, the GUO Asset Store, plugins (the assistant plugins upstream loads are Windows DLLs), the web and Android exports from a Linux host.

Scripted runs without a window

Godot opens its window on your desktop. For probes and screenshots that should not take the screen, run the engine under a virtual display:

GODOT_CONSOLE=~/bin/xvfb-godot launchers/dev/playtest.sh

where ~/bin/xvfb-godot is a two-line wrapper of your own, pointing at your clone's engine:

#!/bin/sh
exec xvfb-run -a -s "-screen 0 1920x1080x24" /path/to/GUO/tools/godot/Godot_v4.7.2-stable_mono_linux_x86_64/Godot_v4.7.2-stable_mono_linux.x86_64 --audio-driver Dummy "$@"

GODOT_CONSOLE in the environment wins over the pinned engine, as every setting does.