Minecraft Java Edition Server – How to Enable Cheats for Players via Console

Your server needs to connect to minecraft.net so it can verify that everyone who connects has a legitimate and unhacked version of the game. You can test this by using the ping minecraft.net command from the Command Prompt.

However, another option which would open your server up to hackers is to turn off the authentication. In your server configuration file, just add the line online-mode=false and you should have no problems connecting then. However, any hackers could join your server and wreak havoc so be warned.

ADDITION

If that doesn't work for you, ensure that you have the correct minecraft_server.jar file. The correct one can be found ate the bottom of the Minecraft Downloads page. The one on the servers page is often out of date.

My recommended solution for this kind of thing tends to be "Use The System!".

If you have the option, enabling Time Machine from system preferences to create a full disk backup every hour is usually a good idea, and if you don't have the opportunity, you might want to consider getting an external disk and implementing that approach.

If that is completely out of the question for whatever reason, the alternative is using cron.

Setting up the interval running is easy enough, a simple man crontab should give you the information you need on that; but having a script to actually do the backup might be useful:

#!/bin/sh
cd ~/Desktop/MinecraftServer # or the path to your minecraft server directory
rm -rf world.bak
cp -r world world.bak

Save this as a "minecraft_server_backup.sh" and chmod +x it.

This particular script only keeps the most recent backup, and additionally, it doesn't actually check if the server is running before making a backup.