Moving towards another object

Scripting
1

I want one object to “chase” another. If I get the position of the other object in the Update function, is there some function I can use to say “move closer to this position”, or do I have to calculate the direction myself?

2

could you not look at the target and have it move forward?

var target : Transform; 

function Update(){
    transform.LookAt(target);
}