How to select the world for server.exe?

[Laeffy]

please help

[xXx_Ape_xXx]

Not entirely sure what you're asking, but these might be helpful:

Server startup parameters

Server Config

[Thorfinn]

If I'm guessing what you are asking properly, what you want is about halfway down the page of the Server Config link that @xXx_Ape_xXx posted 

    // Point to world file which should be loaded on server start (or created if not exists).
    "SaveFileLocation": "/absolute/path/to/Save/world_file.vcdbs",