Command Block

{{Block Tile Entity
 * type=Solid Block
 * gravity=No
 * dirt=No
 * transparent=No
 * light=No
 * tool=N/A
 * renewable=No
 * stackable=Yes (64)
 * entityid=Control
 * data=137
 * firstver=12w32a
 * nonrenewable=yes

The Command Block is a block made with the intent to support Adventure mode and will allow mapmakers to expand the interaction with the player through server commands. The block can run specified server commands when activated by redstone current. Considering its functionality, they will not be able to be crafted and only administrators will be able to place them. To be able to use this block in multiplayer, you must replace  by   on line   in server.properties. If this line doesn't exist, you'll have to add it. Currently, it is not in creative mode inventory.

Usage
The Command Block will execute server commands like giving items or experience to a player.

To change the command executed by the block, simply right-click it, and a GUI will open. Despite the fact that the chat function allows 100 characters, the command block only allows 32.

In place of player names, it is possible to use multiple different shorthands:

When using commands, treat them as if entered from the console - you always need to specify the target, so it is not possible to use commands such as "kill" which do not take a player argument.

So for example, to change the mode to survival for the nearest player: /gamemode survival @p

Note that you will have to be in Creative Mode to change the command associated with the block.

Disabled commands
As of 12w32a, these commands have been disabled for the Command Block. {| class="wikitable" ! Command ! Reason for being disabled
 * /kick
 * rowspan="2" | Due to @a, this could be used to lock out a server from entries.
 * /ban
 * /op
 * So players cannot OP themselves.
 * /deop
 * So players cannot deop OPs.
 * /stop
 * So players cannot shut down a server.
 * /deop
 * So players cannot deop OPs.
 * /stop
 * So players cannot shut down a server.
 * So players cannot shut down a server.


 * However "/me" command still works and allows to broadcast messages server-wide. Command block identifies itself as "@". Worth noting is the fact that "/me" command, is an example of command without player target that actually works with Command block.

History
On July 27th, 2012, Jeb began tweeting of a new block he had created to start expanding Adventure mode. He began posting pictures, ideas and hints of what the block will be able to do. During Notch's AMA he hinted the block may be in 1.4.

Trivia

 * the gray square from the sprite isn't perfectly in the middle.

Tutorials
 Smallest way to build a weather/time machine using the new command blocks.