XEmacs Reference Manual - File Names Go to the previous , next section. Most Emacs commands that operate on a file require you to specify the file name.
Completion is available, to make it easier to specify long file names.
See section Completion . There is always a default file name which is used if you enter an empty argument by typing just RET . Each buffer has a default directory, normally the same as the directory of the file visited in that buffer. When Emacs reads a file name, the default directory is used if you do not specify a directory. If you specify a directory in a relative fashion, with a name that does not start with a slash, it is interpreted with respect to the default directory.