Command Blocks

Note: To learn how to give yourself a command block, check out Starting Out With Commands.

Types
There are currently 3 types of command blocks. They all have different uses, and they are all very useful. They are: When you click the command block to go into the console, you will get a page with the console interface. There is one box to enter your command, and then three other boxes you can click on.
 * 1) The Repeating Command Block
 * 2) The Chain Command Block
 * 3) The Impulse Command Block

To get a repeating command block, click the one on the left until it says Repeating. Repeating command blocks activate their command every millisecond they have redstone power. Be careful, though, as it can lag out your world.

To get a chain command block, click the one on the left until it says Chain. Chain command blocks activate when two parameters are fufilled: The command block has redstone power, and a command block facing into it activates.

The impulse command block is already set when you place your command block, seen as Impulse. Impulse command blocks activate once they get redstone power. After they are powered, that redstone must be turned off, and it must be powered again.

Conditional/Unconditional
These types affect when a command block activates. They are seen in the middle option.

Unconditional command blocks are the default type, labeled by Unconditional. Unconditional command blocks activate whenever their type's parameter are active.

Conditional command blocks are labeled by Conditional. Conditional command blocks only activate when the command block facing into it provides a true output, as well as needing the parameters of their type.

Needs Redstone/Always Active
These types affect the redstone power of the command block. They are seen in the rightmost option.

Needs Redstone command blocks are the default type, labeled by Needs Redstone. Needs Redstone does nothing to the command block.

Always Active command blocks labeled by Always Active. They act as if as they are always powered.

Why To Use Command Blocks
Command blocks are extremely useful in alternative to manual coding. A few reasons are:
 * 1) They are useful for adventure maps. In a map, you don't exactly want your player to have access to cheats and essentially have to create the game themselves! It's much easier just to have command blocks automatically do the work behind the scenes.
 * 2) They require no manual work. If you're going to be playing a game a lot of times, you're going to want to come back to the game with it already prepared for you instead of spending hours resetting every block.
 * 3) They can be used in place of redstone machines and contraptions. The days of redstone are in the past! Why spend time making robots that are bulky and look like moving slime when you could see a 100% automatic bot with no external power source fly across the room and do a dance? Command blocks make hard things easy and simple things simpler.