Without going into too much detail that is really irrelevant, I am creating a file using redirection (i.e. >&) that ultimately, from past experience, will take many hours to produce. (I'll just say that it has to do with an external hard drive connected via a USB port.) Well, I'd like to "check up" on the "progress" this program has made so far periodically, and one way of doing this is via the "List' command on the file being produced via redirection and scrolling down to the bottom (the "end" key followed by scrolling down to the very bottom) and looking at the line number displayed in the "List" command's title bar. However, I'm really only interested in the number of lines this file contains rather than actually looking at the contents of the file, and the "@Lines" function would be the perfect way to find that out. However, attempting to use it on this file yields "TCC: (Sys) The process cannot access the file because it is being used by another process." So the question(s) are simple: Why can't "@Lines" read the file to count the number of lines it contains whereas the "List" command can read it and is there any easy way to just determine how many lines the file contains at any given point in time?