Unloading Main World

I'm developing a plugin that will replace all of a server's worlds with files stored in another folder. If I understand correctly, the only to modify these files using a plugin is to first unload the worlds.

Unfortunately, I haven't been able to unload these worlds. I've looked at other threads and have tried a multitude of fixes, unloading chunks first, saving the world first, etc. I read that the unloadWorld() method will fail if the world is the main one (index 0). Is there another way to unload the main world?

Please note that since I am replacing all of the worlds at the same time, I can kick players but can't teleport them to another world.

Thanks!

 

@timtower The plugin might modify other files on the Minecraft server, and I'm afraid something bad may happen if there are players online, which may make the server write to those files.

 

@timtower Doesn't the server need to be running for plugins to work?

 

@timtower It needs to run from a plugin.

Would it be best or even possible to run a bash script from the plugin before the server goes online?

EDIT by Moderator: merged posts, please use the edit button instead of double posting.

 

The paid plugin EasyBackup seems to be able to do this though. See here: https://julianstaudt.de/wiki/eb/commands-permissions

I would ask them how they did it, but it's a paid plugin so I imagine they won't tell me.