Description

A way to append the file instead of overwriting it.

Code Snippet

(defun org-babel-tangle-append ()
  "Append source code block at point to its tangle file.
The command works like `org-babel-tangle' with prefix arg
but `delete-file' is ignored."
  (interactive)
  (cl-letf (((symbol-function 'delete-file) #'ignore))
    (org-babel-tangle '(4))))

(defun org-babel-tangle-append-setup ()
  "Add key-binding C-c C-v C-t for `org-babel-tangle-append'."
  (org-defkey org-mode-map (kbd "C-c C-v +") 'org-babel-tangle-append))

(add-hook 'org-mode-hook #'org-babel-tangle-append-setup)