Q:Problem
S:Reason and Solution

Q:
默认状态下刚刚启动steamCMD时报错

Loading Steam API…Failed to init SDL priority manager: SDL not found

S:

This is an error caused by the absence of the 32-bit SDL library.

sudo apt install libsdl2-2.0-0:i386

solves the problem.

Q:
潜渊症无法运行(怀疑与linux下运行.exe有关，以及libsdl2-2.0)

A:
与.exe似乎无关
https://github.com/Regalis11/Barotrauma/issues/2310#:~:text=Preface%3A%20I%27m%20running,get%20it%20working.

个人实践的情况：不需要创建exe的ln，需要添加appid.txt，需要创建sdk64文件夹，需要建立.so的符号链接。./DedicatedServer运行即可手动启动服务器。

Preface: I'm running Ubuntu 18.04.4 LTS (GNU/Linux 4.15.0-1060-aws x86_64) with 8GB of RAM. I've run sudo dpkg --add-architecture i386 to add repositories necessary to install some dependencies.

I can now reproducibly get the server to boot from a clean install.
EDIT: Edited to reflect latest update.

Instructions for getting to boot
"Using" steamcmd:
NB: If you installed steamcmd manually, the server root directory listed will probably be different to the tune of ~/Steam/steamapps/common/Barotrauma\ Dedicated\ Server/.

Run steamcmd +login anonymous +app_update 1026340. If you installed steamcmd manually, use ./steamcmd.sh +login anonymous +app_update 1026340 instead. Expected final output should be Success! App '1026340' fully installed.
Make sure that the directory ~/.steam/sdk64/ exists, i.e. mkdir -p ~/.steam/sdk64.
Create a symlink as follows: ln -s ~/.steam/SteamApps/common/Barotrauma\ Dedicated\ Server/DedicatedServer ~/.steam/SteamApps/common/Barotrauma\ Dedicated\ Server/DedicatedServer.exe. This is because the executable was moved to just be called DedicatedServer. Check it was linked (should be light blue when you ls). NB: this has been fixed now.
Create a symlink as follows: ln -s ~/.steam/SteamApps/common/Barotrauma\ Dedicated\ Server/linux64/steamclient.so ~/.steam/sdk64/steamclient.so, and check it works (should be light blue when you ls).
Create a file in the root directory of the server called steam_appid.txt (~/.steam/SteamApps/common/Barotrauma\ Dedicated\ Server/steam_appid.txt) with content 602960, Barotrauma's Steam App ID (shocking, I know). NB: this has been fixed now.
Run the server directly, i.e. cd ~/.steam/SteamApps/common/Barotrauma\ Dedicated\ Server/ and then ./DedicatedServer. The server should boot, with final output Server started. To get it to run in the background, use screen or something. NB: you can run from steamcmd +login anonymous +app_run 1026340 now.