Command Block

A command block is a block that can execute commands. Because it cannot be obtained in survival mode without cheats, it is primarily used on multiplayer servers and in custom maps.

Obtaining
A command block cannot be broken in survival mode, is not flammable, and has the same blast resistance as bedrock. A command block cannot be moved by a piston, but can be destroyed by an Ender dragon.

Command blocks are not available in the creative inventory, but can be obtained via "pick block" or various commands, such as

Usage
A command block can execute commands when activated by redstone power.

Modification


To enter or modify the command in a command block, right-click on the command block to open the command block GUI. The GUI will only open if the player is in creative mode, and has the proper permissions. In singleplayer, cheats must be enabled to edit command blocks. In multiplayer, command blocks can only be edited successfully by operators in creative mode, and for command blocks to work at all the following values must be set in the server.properties file:
 * must be set to
 * must be set to  or above (default is 4)


 * Console Command


 * Commands can be entered in the top text pane. The text limit for commands in a command block is 32,767 characters, but the text pane can only show a small portion of this amount at a time.


 * Commands in a command block do not need to be prefixed with the forward slash as they do in the chat window, but using it will still work.


 * Below the console command text pane are some reminder tips about how to use target selectors.


 * Previous Output


 * The bottom text pane doesn't appear until the command block has been activated at least once. Its text is not editable and shows the output message of the last executed command (success or failure). The command block GUI allows the player to choose whether the last output should be stored and displayed in the Previous Output text pane. A button to the right of the Previous Output text pane shows  when the output should be stored and   when the output should not be stored. For worlds with many command blocks, not storing the output text can reduce memory and storage requirements.


 * Done


 * Click the "Done" button or to save the command and leave the command block GUI.


 * Cancel


 * Click the "Cancel" button or to leave the command block GUI without saving any changes.

Activation
Command blocks are redstone mechanisms and can be activated by:
 * An adjacent active power component: for example, a redstone torch (except that a redstone torch will not activate a command block it is attached to), a block of redstone, a daylight sensor, etc.
 * An adjacent powered block (for example, an opaque block with an active redstone torch under it)
 * A powered redstone comparator or redstone repeater facing the mechanism component
 * Powered redstone dust configured to point at the command block (or on top of it) or directionless; a command block is not activated by adjacent powered redstone dust which is configured to point away from it.

In addition, a command block will activate when it is placed by a dispenser (only if the dispenser is directly powered), using the command specified in the command block item's BlockEntityTag. When a command block is cloned by a command to a powered location, the new command block will only execute its command if the original has never been activated (visible in the F3 debug screen as "triggered").

When activated, a command block will try to execute its command.

Output
When activated, a command block can produce two types of output:


 * Redstone Comparator


 * A command block can power a redstone comparator facing away from it (possibly separated by a block) with a signal strength specific to the last executed command (for example, the number of players affected by the command).


 * The signal strength always reflects the last command executed, even after the command block is deactivated.


 * Message


 * The output message describes the success or failure of the executed command, and may be written to multiple destinations:


 * Previous Output: The output message is always written to the "Previous Output" text pane of the command block GUI.


 * Chat: The output message is written to the chat text in singleplayer mode, or broadcast to all other ops in multiplayer mode, unless it has been suppressed with . Some commands may write additional text to the chat as their normal function which won't be suppressed (for example, the command will write a message to the chat of all players), separate from the output message. Chat messages which would usually be prefaced by a player's name (such as from the,  and  commands) use   as the player name. If the command block had been named in an anvil before placement, that name will be used instead.


 * Logs: The output message is written to multiplayer server logs unless it has been suppressed with.


 * Command Stats


 * Command blocks can post various success results to scoreboard objectives, including:
 * SuccessCount: the number of successes (previously also available by redstone comparator output, but not limited to 15)
 * AffectedBlocks: the number of blocks that were altered
 * AffectedEntities: the number of entities that were altered (including players)
 * AffectedItems: the number of items that were altered
 * QueryResult: value returned by command


 * The objectives to be used can be specified by running the command or by modifying the command block's NBT data directly with the  command.

Data values
A command block has an ID name of  and is further defined by its block data and block entity. A command block also has a block state which is expected to replace the functionality of block data in a future version.

Block data
A command block's block data specifies whether the command block is currently activated.

Block entity

 * Block entity data
 * : X coordinate of the Block Entity.
 * : Y coordinate of the Block Entity.
 * : Z coordinate of the Block Entity.
 * : Optional. The name of this command block, which will replace the usual '@' when using commands such as "say" and "tell".
 * : The command to issue to the server.
 * : Represents the strength of the analog signal output by redstone comparators attached to this command block. Only updated when the command block is activated with a redstone signal.
 * : The last line of output generated by the command block. Still stored even if the gamerule commandBlockOutput is false. Appears in the GUI of the block when right-clicked, and includes a timestamp of when the output was produced.
 * : 1 or 0 (true/false) - Determines whether or not the LastOutput will be stored. Can be toggled in the GUI by clicking a button near the "Previous Output" textbox. Caption on the button indicates current state: "O" if true,"X" if false.
 * : Information identifying scoreboard parameters to modify relative to the last command run.
 * : Player name to store success of the last command. Can be a player selector but may only have one resulting target.
 * : Objective's name to store the success of the last command.
 * : Player name to store how many blocks were modified in the last command. Can be a player selector but may only have one resulting target.
 * : Objective's name to store how many blocks were modified in the last command.
 * : Player name to store how many entities were altered in the last command. Can be a player selector but may only have one resulting target.
 * : Objective's name to store how many entities were altered in the last command.
 * : Player name to store how many items were altered in the last command. Can be a player selector but may only have one resulting target.
 * : Objective's name to store how many items were altered in the last command.
 * : Player name to store the query result of the last command. Can be a player selector but may only have one resulting target.
 * : Objective's name to store the query result of the last command.
 * : Objective's name to store the query result of the last command.

Issues
Befehlsblock Bloque de comandos Bloc de commande Opdrachtblok Blok poleceń pt-br:Bloco de Comando Командный блок 命令方块