Emacs: Show Whitespaces

whitespace-mode makes whitespaces visible {spaces, tabs, newlines}.

whitespace-mode is new in Emacs 23 (date 2009-07)

Alt+x whitespace-mode

Make whilespace visible. Toggle on/off, for current file.

Alt+x global-whitespace-mode

Do it in every buffer.

Alt+x whitespace-newline-mode

Make just newline character visible.

Alt+x global-whitespace-newline-mode

Do it in every buffer.