Emacs: Copy File Path of Current Buffer 💠

Here's a command to copy the file path of current buffer.

(defun xah-copy-file-path (&optional DirPathOnlyQ)
  "Copy current buffer file path or dired path.
Result is full path.
If `universal-argument' is called first, copy only the dir path.

If in dired, copy the current or marked files.

If a buffer is not file and not dired, copy value of `default-directory'.

URL `http://xahlee.info/emacs/emacs/emacs_copy_file_path.html'
Created: 2018-06-18
Version: 2021-09-30"
  (interactive "P")
  (let ((xfpath
         (if (eq major-mode 'dired-mode)
             (progn
               (let ((xresult (mapconcat #'identity
                                         (dired-get-marked-files) "\n")))
                 (if (equal (length xresult) 0)
                     (progn default-directory )
                   (progn xresult))))
           (if buffer-file-name
               buffer-file-name
             (expand-file-name default-directory)))))
    (kill-new
     (if DirPathOnlyQ
         (progn
           (message "Directory copied: %s" (file-name-directory xfpath))
           (file-name-directory xfpath))
       (progn
         (message "File path copied: %s" xfpath)
         xfpath )))))

Be sure to give it a easy key. 〔see Emacs Keys: Define Key〕