I want to open a file inside Emacs which is located on a remote server, with sudo powers on the server. I can open local files with sudo via Tramp like this:
C-x C-f /sudo::/home/user/file
But I want to use sudo on the server:
C-x C-f /sudo::user@server/home/user/file
But this gives me sudo powers on my local machine, it asks for my sudo password on the local machine. Is there a way to use sudo on the server?
BTW: Emacs is not installed on the server
You have to ssh into the server first, then you have to run emacs locally.
Or you can use NFS with no_root_squash, or you can try with emacs server/client, although I have no idea of what may happen (do not use emacs myself)
I think multi-hop filenames in tramp is what you're looking for.
The first hop would be ssh and the second would be sudo.
Update: Recent versions of emacs support multiple hops using proxies:
(add-to-list tramp-default-proxy-alist ("my-sudo-alias" nil "/ssh:user@ssh-host"))
then invoke by opening:
/sudo:my-sudo-alias:file-on-ssh-host
I had some troubles with the selected answer. However, it worked when I added this line to .emacs:
(add-to-list 'tramp-default-proxies-alist '(".*" "\`root\'" "/ssh:%h:"))
And then executed the following:
/sudo:ssh-host:file-on-ssh-host
It was slightly confusing because at one point I was prompted for the "root" password, but entering my user's password granted me access. It also universally works on all hosts on the network. Also, I can still do this to not be root:
/ssh:ssh-host:file-on-ssh-host