Xah Lee has a page up on batch text processing with Emacs. The page is a recapitulation of several tips that Lee has published before. These tips were very helpful to me when I was trying to learn the Elisp environment. Anyone with some Common Lisp or Scheme experience will have no problem with the Elisp language; it’s the library of Elisp functions specific to Emacs that will be unfamiliar. Lee’s tips helped me understand and learn the Elisp idioms.
If you are trying the learn Elisp, it’s worthwhile taking a look at this page and some of the other in Lee’s Elisp Tutorial.