Java Edition:Command Block (Block)
Command blocks cannot be placed into a world without both creative and operator status, regardless of if you have the Command Block (Item) itself. There are exploits that allow them to be placed without these requirements.
Obtaining
Pre 1.9 Placement Rules
From their introduction in 12w32a to 15w33c (a 1.9 snapshot), command block items could be placed in survival without restriction. This only allows for the default command block to be placed, as the repeating and chain variants did not exist before the restriction was implemented. If one used Any NBT on Any Item methods to obtain command blocks with command NBT, this method would not place them with commands inside.
Dispensing
From 14w07a (a 1.8 snapshot) to 1.8.5, command blocks that were placed inside dispensers could be placed into the world. If one used the Any NBT on Any Item methods to obtain command blocks with command NBT, then this method also allows them to be placed into the world and execute their commands.
Word Tearing and Any Falling Block via Asynchronous Threads
From 14w32a (1.8 snapshot) to 17w46a (1.13 snapshot), asynchronous block updates allow for block palette corruption, and this corruption, when combined with the registry palette type, can allow for the creation of any block that can exist, such as command blocks. Asynchronous block updates also allow for usage of the "generic method" to create a falling block entity of any existing block in your world.
These falling blocks may also be used to obtain their respective item, if it exists in item form, such as end portal frames. Blocks such as end gateways cannot be obtained as items with this method, as they have no corresponding item. Falling blocks also allow for the placement of both blocks that cannot normally be placed, either due to operator restrictions (e.g. command blocks) or not having an item form (e.g. end gateways).
22w13oneBlockAtATime Endermen Spawning
Endermen in the April Fools' version 22w13oneBlockAtATime spawn carrying random blocks. One of these blocks they can spawn with is each command block variant. There are 902 different blocks that are equally likely for them to spawn with and so there is a 1/902 = 0.11% chance of the enderman spawning with this block specifically. If the enderman spawns holding a generic_item_block (1/902) there's also a 1/1105 chance it will be this block as its block state, but there's only a 0.0001% chance of this occurring.[1]
In the version, the block can be received from the enderman by angering it then letting it attack the player with an open hand. This will cause the block to transfer into the player's hand. Also, if the enderman dies and the falling block launches from the enderman, this can be picked up by the player. The items can be stored in 22w13oneBlockAtATime by switching the block from carrying to the offhand, shift right-clicking onto a donkey/mule with a chest, and then swapping the item into a slot. Additionally, the enderman carrying the block can be updated and then killed in a later version to obtain the item.
The Place Block
In the April Fool's snapshot 23w13a_or_b, if the vote place_block is enabled, then one can craft and place the Place Block. By putting a command block in an inventory (e.g. a chest) behind this block and powering it, the block will be placed into the world.
See also
References
- ↑ 1/902 * 1/1105 ≈ 0.0001%