Edit file as another user in Emacs
##################################

:date: 2016-11-10T08:57:12Z
:category: blog
:tags: development,emacs
:url: 2016/11/10/edit-file-as-other-user-in-emacs/
:save_as: 2016/11/10/edit-file-as-other-user-in-emacs/index.html
:status: published
:author: Gergely Polonkai

I have recently found `this article <http://emacsredux.com/blog/2013/04/21/edit-files-as-root/>`_
by Bozhidar Batsov on opening the current file as root.  I barely use `tramp
<https://www.gnu.org/software/tramp/>`_ for sudo access, but when I do, I almost never use root as
the target user.  So I decided to fix it for my needs.

.. code-block:: lisp

   (defun open-this-file-as-other-user (user)
     "Edit current file as USER, using `tramp' and `sudo'.  If the current
   buffer is not visiting a file, prompt for a file name."
     (interactive "sEdit as user (default: root): ")
     (when (string= "" user)
       (setq user "root"))
     (let* ((filename (or buffer-file-name
                          (read-file-name (format "Find file (as %s): "
                                                  user))))
            (tramp-path (concat (format "/sudo:%s@localhost:" user) filename)))
       (if buffer-file-name
           (find-alternate-file tramp-path)
         (find-file tramp-path))))

If the user is not specified, the default is still root.  Also, if the current buffer is not
visiting a file, I prompt for a filename.  As I’m not an ``ido`` user, I didn’t bother calling
``ido-read-file-name``; `helm <https://github.com/emacs-helm/helm/wiki>`_ overrides
``read-file-name`` for me anyway.

Unlike Bozhidar, I barely use this feature, so I didn’t bind this to a key.