I have my emacs running as server and two small wrapper scripts ec and et which connect to it with emacsclient (either creating a new frame or opening a terminal frame).
Because I want to do all my system administration (editing files in /etc/) with emacs and don’t want to start another emacs instance as root, I use TRAMP to switch to superuser mode automagically if the opened file is read-only.
Here’s the code (UPDATED: Uses defadvice instead of hooking into find-file-hook, which had the bad effect of find-file-hook running twice.):
(defun th-rename-tramp-buffer () (when (file-remote-p (buffer-file-name)) (rename-buffer (format "%s:%s" (file-remote-p (buffer-file-name) 'method) (buffer-name))))) (add-hook 'find-file-hook 'th-rename-tramp-buffer) (defadvice find-file (around th-find-file activate) "Open FILENAME using tramp's sudo method if it's read-only." (if (and (not (file-writable-p (ad-get-arg 0))) (y-or-n-p (concat "File " (ad-get-arg 0) " is read-only. Open it as root? "))) (th-find-file-sudo (ad-get-arg 0)) ad-do-it)) (defun th-find-file-sudo (file) "Opens FILE with root privileges." (interactive "F") (set-buffer (find-file (concat "/sudo::" file))))
Now whenever I type ec /some/file/i/have/no/permissions/to/write (or emacsclient [-c|-t] /some/root/file, emacs asks me to re-open it using TRAMP’s sudo method.