how to make bullets apply damage

im making a fps game and i need a code that will make my bullets damage enemies.

what bullets are you using is it raycast or actual bullets
if its a raycast one add this code

 var damage:float = 4;
    function Update () {
    //your fire bullet code(rate of fire,bullet--;//.etc)
    var hit:RaycastHit;
    //physics raycast code

if(hit.transform.tag =="Enemy"){



if it is an actual bullet then creaate sendmessage option in same way(using OtriggerEnter or similar ones)

To apply damage add this code to your enemy

var life:float = 100;

function Damage(damage:float){