the following is output from a terminal session demonstrating that I, hopefully actually set this up right.
~ $cat .emacs
(require 'package)
(custom-set-variables
;;lots of comments generated by computer
'(package-archives (quote(("gnu" . "http://elpa.gnu.org/packages")
("marmalade" . "http://marmalade-repo.org/packages")
("melpa" . "http://melpa.milkbox.net/packages/")
("org" . "http://orgmode.org/elpa")))))
(custom-set-faces
;;again lots of comments added by the computer
)
(add-to-list 'load-path "/usr/share/emacs/24.3/site-lisp/mu4e")
~ $ ls /usr/share/emacs/24.3/site-lisp/mu43
#there are a lot of files here, but I am only going to show 2 right now
mu4e.elc
mu4e.el
... and yet emacs M-x mu4e returns [no match]. I have checked to load-path variable, and it is there. What am I doing wrong?