CVS commands follow this form:
cvs [GLOBAL_OPTIONS] COMMAND [OPTIONS] [FILES]
The second set of options is sometimes called command options. Because there are so many of them, though, I'll just call them "options" in most places to save space.
Many commands are meant to be run within a working copy and, therefore, may be invoked without file arguments. These commands default to all of the files in the current directory and below. So when I refer to the "file" or "files" in the text, I'm talking about the files on which CVS is acting. Depending on how you invoked CVS, these files may or may not have been explicitly mentioned on the command line.