Hi
@Buddha9099 !
I recently downloaded the linux version and saw the same thing. However upon closer inspection this file is actually an executable without a file extension. You should be able to run that file from a command line using ./<filename>. I did this on the linux version and it kicked off the download of the actual server.
UPDATE: Once you have the server running, it's going to crash. This is because the latest build is trying to load "CustomMainMenu " which is a client-side mod. To disable this mod, append .disable to the end of the CustomMainMenu JAR file in the mods directory.
You will get one more error on launch... it will tell you that you didn't accept the EULA even though you accepted it when you launched the server. Modify the EULA and add "true" in there, launch one more time and you should be running.
Hope this helps,
MrCrow