It is recommended to make lines no longer than 80 columns. This page shows configuration for text editors to alert you when you exceed that limit.
Emacs: column-maker
Mark the character that is on position 80 in exceeding lines:
(require 'column-marker) (add-hook 'erlang-mode-hook (lambda () (interactive) (column-marker-3 80)))
Emacs: Highlight lines longer than 80 chars
Related: http://www.emacswiki.org/emacs/EightyColumnRule http://raebear.net/comp/emacscolors.html
(custom-set-faces
; Tabs characters:
'(my-tab-face ((((class color)) (:background "orange"))) t)
; Spaces at end of line
'(my-trailing-space-face ((((class color)) (:background "green"))) t)
; Lines longer than 80 characters:
'(my-long-line-face ((((class color)) (:background "yellow")) t))
(add-hook 'font-lock-mode-hook
(function
(lambda ()
(setq font-lock-keywords
(append font-lock-keywords
'(("\t+" (0 'my-tab-face append))
("^.\\{81,\\}$" (0 'my-long-line-face append))
("^.\\{81\\}\\(.+\\)$" (0 'my-long-line-facee append))
("[ \t]+$" (0 'my-trailing-space-face append))))))))
Vim:highlight exceeding characters
Add in $HOME/.vimrc
highlight OverLength ctermbg=red ctermfg=white guibg=#592929 match OverLength /\%81v.\+/
