THERE SEEMS TO BE ISSUES WITH SOME VERSIONS OF UBUNTU
This page was tested and known working with Ubuntu 24.04.
At least 1 person has had issues with Ubuntu 22.04 not working. Based on discord logs, maybe a few people.
This assumes .net and steam cmd are already installed and can be found / executed by running a command ex dotnet --info or steamcmd in the cli
Steps I Took
create a directory.
mkdir sbox2
Open SteamCMD (assuming installed already)
steamcmd
force install dir
force_install_dir /home/derrik/sbox2
login
login anonymous
Update
app_update 1892930
should end with Success! App '1892930' fully installed.
Fixing “required file not found”
Use dos2unix to unfuck the files, i think its just line endings so use w/e tool you want.
Final
Example start script from docs
#!/bin/bash
./sbox-server.exe +game facepunch.sandbox facepunch.flatgrass +hostname "My Dedicated Server"