To copy the Minecraft ID for Command Block, simply click the "Copy to Clipboard" button to the right.
If you are using the Essentials Bukkit Plugin, you can give this item to yourself by entering the following command:
To give this item to yourself in Minecraft, enter the following command:
The command block in Minecraft can be used to execute commands. They cannot be obtained in Vanilla MC but, by using the item id, you can spawn the command block item into your inventory when in creative mode. In many cases, you must be a server op to use the block. Modifiers such as @p and @e can be used to target things like players and entities with commands.