GNU Emacs Lisp Reference Manual
When you start Emacs, it normally attempts to load the file
.emacs from your home directory. This file, if it exists, must
contain Lisp code. It is called your init file. The command line
switches -q and -u affect the use of the init file;
-q says not to load an init file, and -u says to load a
specified user's init file instead of yours. See Entering Emacs.
A site may have a default init file, which is the library named
default.el. Emacs finds the default.el file through the
standard search path for libraries (see How Programs Do Loading).
The Emacs distribution does not come with this file; sites may provide
one for local customizations. If the default init file exists, it is
loaded whenever you start Emacs, except in batch mode or if -q is
specified. But your own personal init file, if any, is loaded first; if
it sets inhibit-default-init to a non-nil value, then
Emacs does not subsequently load the default.el file.
Another file for site-customization is site-start.el. Emacs
loads this before the user's init file. You can inhibit the
loading of this file with the option -no-site-file.
"site-start".
If there is a great deal of code in your .emacs file, you
should move it into another file named something.el,
byte-compile it (see Byte Compilation), and make your .emacs
file load the other file using load (see Loading).
See Init File Examples, for examples of how to make various commonly desired customizations in your .emacs file.
nil,
then the default library is not loaded. The default value is
nil.