Editing WoW:API UnitGUID (section)

=== Example: Decomposing a GUID ===
We have a GUID: "0xF530004D2B008852".

First of all, let's find out what kind of unit it is. Take the first three digits in the GUID, ie "F53" (or 0xF53 to show it's an hex value) and apply an AND mask of 0x007 to get 0x003. This GUID is for a normal NPC, neither a pet nor a player.

We can also extract the Unit ID by taking the seventh to tenth digit and converting it to decimal form: "4D2B", or converted to decimal form "19755". A quick visit to wowhead shows that the NPC with that id is "Mo'arg Weaponsmith", [http://www.wowhead.com/?npc=19755]. All "Mo'arg Weaponsmiths" will have that id to identify them.

The last six digits, "008852" is the spawn counter. There will never be two "Mo'arg Weaponsmith", possible even never two mobs in the outside world, with the same spawn number. This spawn counter, combined with the rest makes it possible to always refer to exactly this "Mo'arg Weaponsmith", and not the one next to it.

A simple in game script command can be used to get the NPC ID from your target: ''Target NPC ID: 19755''
 /run print("Target NPC ID:", tonumber((UnitGUID("target")):sub(-12, -9), 16))
More informative script: ''NPC ID("Mo'arg Weaponsmith") = 0x4D2B = 19755''
 /run local a=strsub(UnitGUID("target"),7,10); print("NPC ID(\""..UnitName("target").."\") = 0x"..a.." = "..tonumber(a,16))