How can Minecraft commands be fixed on Mac if they do not function?

Answer 1

SINGLEPLAYER

Referring to slash '/' commands, they only work if the created work has commands enabled. This can be changed by editing the save world file.

Note: When creating a survival mode world, "cheats," as they are called in-game, are initially disabled. Hardcore mode, however, has "cheats" permanently disabled.

MULTIPLAYER

For multiplayer servers, only certain slash commands will work depending on the privileges of the server. Normal users on vanilla servers can use basic commands (/me, /tell, /help), and OP's can use special commands (/give, /tp, /enchant). Modded servers have different privileges and more commands.

Answer 2

What problem are you having specifically? You should be able to download the minecraft_server.jar from the site and run it. Check the MC Wiki for a detailed tutorial on how to start a server.