Saving a non user file with NeoVim, eg root owned /etc/pulse/default.pa

Question

I am using NeoVim v0.4.3. This is the latest version available in repository. I have an Arch build with the most up to date packages and kernel 5.6.4-arch1-1.

Occasionally I edit a file with nvim that I don't have permissions to edit. I only realise this as I am about to save my work.

Recently I edited

/etc/pulse/default.pa

with command

nvim /etc/pulse/default.pa

and no use of sudo.

This file has the following permissions

$ ls -la /etc/pulse/default.pa
-rw-r--r-- 1 root root 4966 Jan 11 18:25 default.pa

So I did some googling and tried to save it with

:w !sudo tee %

and got this error

sudo: a terminal is required to read the password; 
either use the -S option to read from standard 
input or configure an askpass helper

shell returned 1

Press ENTER or type command to continue

It also showed, on the highlighted bar, at the base of the screen, the following

/etc/pulse/default_2.pa [+][RO] 

This did'nt work.

So I tried

:w !echo password | sudo -S tee %

It then displayed the following

:w !echo password | sudo -S tee %                                                                                      
[sudo] password for user:
W12: Warning: File "/etc/pulse/default.pa" has changed and the buffer was changed in Vim as well
See ":help W12" for more info.
[O]K, (L)oad File:

So I pressed O and nothing happened. I then tried :wq and it complained the file was read only.

I then went through the process again and this time pressed L and it showed

:w !echo password | sudo -S tee %
[sudo] password for user:
W12: Warning: File "/etc/pulse/default.pa" has changed and the buffer was changed in Vim as well
See ":help W12" for more info.
"/etc/pulse/default.pa" [readonly] 0L, 0C
Press ENTER or type command to continue

and nvim left me with a blank screen and an overwritten etc/pulse/default.pa file with nothing in it.

I've recovered the file but want to know how to tee the file down to disk when I open the file without the correct permissions.

I'm quite new to vim and think I got this working before but can't for the life of me remember how?

Answer 1

You could try this :W command:

com -bar W exe 'w !sudo tee >/dev/null %:p:S' | setl nomod

Broken down:

"               ┌ write the buffer on the standard input of a shell command (`:h w_c`)
"               │ and execute the latter
"               │
"               │   ┌ raise the rights of the `tee(1)` process so that it can write in
"               │   │ a file owned by any user
"               ├─┐ │
com -bar W exe 'w !sudo tee >/dev/null %:p:S' | setl nomod
"                           ├────────┘ │ 
"                           │          └ but write in the current file
"                           │
"                           └ don't write in the terminal

You may also need to tell sudo(8) which helper program should be executed to read your password.

According to man sudo, there are 2 ways to do it. You can either export the environment variable SUDO_ASKPASS, and assign it the path to the helper program; e.g.:

export SUDO_ASKPASS='/usr/lib/ssh/x11-ssh-askpass'

Here, the helper program is provided by the Ubuntu package x11-ssh-askpass; the name of the package, and the location of the file may differ on your OS. Export the variable from an init file sourced by your shell (e.g. ~/.bash_profile, ~/.zshenv, ...).

Or you can edit the sudo.conf(5) file, and include this directive inside:

Path askpass /usr/lib/ssh/x11-ssh-askpass

---

For more info about the cause of the issue, see this entry in the Neovim FAQ and the links it provides.

Answer 2

There’s a plugin for this. The reason the old :w !sudo tee % doesn't work with Neovim has to do with the refactoring following a client-server architecture, the team is working on a solution though that hopefully will be shipped with 0.5

Answer 3

Try suda.vim : https://github.com/lambdalisue/suda.vim

In case you use vim plug, after plugging it (adding the line) with Plug 'lambdalisue/suda.vim' do a :PlugInstall and thereafter with :SudaWrite instead of the regular :w you will be prompted for a password and can save files as root which have been opened without root permission.

Answer 4

I find a simple method to solve this problem. Just type the password in the first line, then run the command :w !sudo -S tee %.

Thanks for the warning from D. Ben Knoble. I do not aware of this before. I do a test, it turns out that the password can be recovered by undo even had been closed if the persistent undo feature is on.

So, do try this method with cautious!