Turn off wrapping for a single buffer using
(set-default 'truncate-lines t)
This setting does not apply to horizontally-split windows.
‘C-x 3’ splits windows horizontally, where as
‘C-x 2’ splits them vertically.
To turn wrapping on in horizontally-split windows, use the following in your InitFile:
(setq truncate-partial-width-windows nil)
We don’t recommend it, either, because horizontally split windows are usually too small to read anyway. Note that this variable is not buffer-local.
See LineWrap for more info.
See PhysicalLineMove for a minor-mode that changes line movement commands (C-n, C-p, C-a, C-e) to take into account wrapped lines; useful if you don’t want to truncate lines!
If you want to set truncate-partial-width-windows just for a certain mode, you need to put the setting in a hook:
(add-hook 'diff-mode-hook (lambda () (setq truncate-lines t)))
[new] Nano truncates lines so that when you scroll toward the end of one, the line itself moves to the left independently of the rest of the text. I’ve had a surprisingly hard time finding any talk of this feature in emacs. Is it possible?