From the mIRC help file: If the first line in the file is a number, it must represent the total number of lines in the file. If you specify N = 0, mIRC returns the value of the first line if it's a number
Because determining how many lines are in a file is VERY slow. So if you can tell mIRC this information up front, it makes processing much faster. In addition to what Collective said, since you don't want this feature, mIRC lets you disable it. $read(the.file,t,1) The 't' flag tells mIRC you want it to treat the first line as plain text even if it is a number.