Add longlines minor mode to highlight long lines

.emacs.d/init.el

@@ -146,6 +146,20 @@
   (add-hook 'gud-mode-hook
             '(lambda () (setq-local comint-prompt-read-only t))))
 
+(use-package whitespace
+  :config
+  (define-minor-mode whitespace-longlines-mode
+    :lighter    " ll"
+    :init-value nil
+    :global     nil
+    :group      'whitespace
+    (let ((whitespace-style '(face lines-tail)))
+      (whitespace-mode (if whitespace-longlines-mode
+                           1 -1)))
+    ;; sync states (running a batch job)
+    (setq whitespace-longlines-mode whitespace-mode))
+  (add-hook 'prog-mode-hook #'whitespace-longlines-mode))
+
 
 (use-package org
   :defer