In Windows, Emacs is using cr-lf for a linebreak, but I like all my files to use Unix line endings (lf). I found a way to change it during my session, but I am not such an Emacs guru to translate the solution into an elisp command in my .emacs file.
Can anybody help me, so Emacs in Windows will use lf permanently?
As per the comment by Brian Burns, use this for modern Emacs.
(setq-default buffer-file-coding-system 'utf-8-unix)
Prior to Emacs 23.2, you would use
(setq default-buffer-file-coding-system 'utf-8-unix)
See also How to configure GNU Emacs to write UNIX or DOS formatted files by default?