If you use any editor (GNU Emacs or any of the commercial alternatives), you may have written lots of handy LISP programs for use while you're editing. It's convenient to create a separate directory for these; a good name for this directory is (obviously) emacs; it's usually located in your home directory.
If you use GNU Emacs, you should put the following line in the .emacs file:
(setq load-path (append load-path '("
This tells Emacs that it should look in your personal Emacs directory to find your programs. (It's similar to theenvironment variable.)