well the purpose is to check the specified file not containing any existed alias since if its already existed then only the 1st found alias will be triggered by mirc so its will make the specified file cant work correctly :) and for the tokenizing $1 actualy when you use /filter into custom alias you will receive all the result on $1. For example when the result is \"my nickname is zonIRC\" so when you refer it as $1 it will return all of the words but if you refer it as $2 you will not get anything since only $1 is supported.