Well basiclly you have to select a unit to kill it... i got this from mouse sniping... i want to recreate this but don't know how.

I Understand basic eud keys but i don't know how to get the codes for it... can somone help me?

First of all, this in the wrong section. Secondly, what do you mean by EUD keys? Do you mean addresses or EUD key detection, which I assume you don't.

i think he means that he wants a unit to die whenever it gets selected

You and Samsizzle both want to achieve this.... It's very simple. Look at this topic. When the player selects the unit, move the ghost, create an Alexie at that spot and kill the Alexie. This makes it look like you killed the ghost, but the player still has the same ghost so it keeps it's unit number.

I'm 95% sure that if a unit dies, it is replaced by a sprite, which is the dying sprite, then once the sprite's animation is finished, the unit is deleted from memory. The next unit to be created will be placed in the earliest spot in memory (it goes 1, 1700, 1699, etc...). Typically, the earliest spot is the one that just died.