cat function

config.el

@@ -162,3 +162,40 @@
               ("C-TAB" . 'copilot-accept-completion-by-word)
               ("C-<tab>" . 'copilot-accept-completion-by-word)))
 (whole-line-or-region-global-mode 1)
+
+;; very clean me like
+;; (defun concatenate-org-files (directory)
+;;   "Concatenate all .org files in DIRECTORY into a new buffer."
+;;   (interactive "DDirectory: ")
+;;   (let ((output-buffer (generate-new-buffer "*Concatenated Org Files*"))
+;;         (org-files (directory-files-recursively directory "\\.org$")))
+;;     (with-current-buffer output-buffer
+;;       (dolist (file org-files)
+;;         (insert-file-contents file)
+;;         (insert "\n\n"))
+;;       (org-mode)
+;;       (goto-char (point-min)))
+;;     (switch-to-buffer output-buffer)))
+
+(defun concatenate-files-by-extension (directory extension)
+  "Concatenate all files with EXTENSION in DIRECTORY into a new buffer."
+  (interactive
+   (list
+    (read-directory-name "Directory: ")
+    (read-string "File extension (without dot): ")))
+  (let* ((file-regex (concat "\\." (regexp-quote extension) "$"))
+         (output-buffer-name (format "*Concatenated %s Files*" (upcase extension)))
+         (output-buffer (generate-new-buffer output-buffer-name))
+         (files (directory-files-recursively directory file-regex)))
+    (if (null files)
+        (message "No %s files found in the specified directory." extension)
+      (with-current-buffer output-buffer
+        (dolist (file files)
+          (unless (= (point-min) (point))
+            (insert "\n\n"))
+          (insert-file-contents file))
+        (goto-char (point-min))
+        (when (string= extension "org")
+          (org-mode)))
+      (switch-to-buffer output-buffer)
+      (message "Concatenated %d %s files." (length files) extension))))