Hey! This is a guide on how the new /function command works. lets start with what it does:

The /function command is a new command that was added in 1.12 Pre Release 1, and It basically allows players to put commands into a file outside of the game and activates the commands in a single tick in game.

The Command: How the command works is right here ---> so right now i want to make a function command that looks like this: /function items:diamonds
So what I want it to do is say in the chat "Given 1 Diamond to Gavin" and Give Me the diamond.
So what I do now is go outside the game, and i want to get to the Minecraft folders, and once you get there, click saves, then The World you are operating this on, click Data, and finally click functions.
Once you are in the functions folder, you are going to want to make a file with the command inside it, Im using a Mac computer, which means i have to create a file with TextEdit. once I'm in TextEdit, you're going to want to put the command you want in it.
Here are the commands inside the file:

/say Given 1 Diamond to Gavin
/give gavinthepowerful diamond 1

After we do that, we are going to close the file and name it "diamonds". And to create the final piece of it all, you need to create a folder and I would name it "items".
After all that work, you want to put the "diamonds" file into the "items" folder.

Once you finished all the above, go back into your Minecraft world and type /reload
And to run the command you need to do /function items:diamonds
And if all went well, we should have a diamond and the chat tell us we got a diamonds!

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