Recently we came across the problem of opening a large log file to read only the last few lines of the logs. This log file is a cumulative log file i.e. it had grown to be over 8GB in size. Not even Notepad++ could open it. We could probably find a efficient editor to do this job for us, but decided to read the end of the file ourselves.
Here is a C# snippet to read in the last n% of any file: