Programmatically Deleting Data from a File

Question

I am trying to find a way to remove data from a file using C#. I know how to edit using FileStream.Seek and a StreamWriter, and I know how to append data to the end, but I haven't found a way to actually remove data from the end of a file. Due to file size and memory constraints, reading the whole thing in, saving it as a new file, and then deleting the old file is not an option. Is there a way to write an EOF where I specify, and that's that? (if so, how do you actually do that?) Or do I have to go about doing this some other way? Thanks in advance for the help, Jonathan Mitchem