How to Get Sudo Access for a File Inside the Vi Text Editor

How do you get sudo access for a file inside the vi text editor?

% is replaced with the current file name, thus you can use:

:w !sudo tee %

(vim will detect that the file has been changed and ask whether you want to it to be reloaded. Say yes by choosing [L] rather than OK.)

As a shortcut, you can define your own command. Put the following in your .vimrc:

command W w !sudo tee % >/dev/null

With the above you can type :W<Enter> to save the file. Since I wrote this, I have found a nicer way (in my opinion) to do this:

cmap w!! w !sudo tee >/dev/null %

This way you can type :w!! and it will be expanded to the full command line, leaving the cursor at the end, so you can replace the % with a file name of your own, if you like.

How does the vim write with sudo trick work?

In :w !sudo tee %...

% means "the current file"

As eugene y pointed out, % does indeed mean "the current file name", which is passed to tee so that it knows which file to overwrite.

(In substitution commands, it's slightly different; as :help :% shows, it's equal to 1,$ (the entire file) (thanks to @Orafu for pointing out that this does not evaluate to the filename). For example, :%s/foo/bar means "in the current file, replace occurrences of foo with bar." If you highlight some text before typing :s, you'll see that the highlighted lines take the place of % as your substitution range.)

:w isn't updating your file

One confusing part of this trick is that you might think :w is modifying your file, but it isn't. If you opened and modified file1.txt, then ran :w file2.txt, it would be a "save as"; file1.txt wouldn't be modified, but the current buffer contents would be sent to file2.txt.

Instead of file2.txt, you can substitute a shell command to receive the buffer contents. For instance, :w !cat will just display the contents.

If Vim wasn't run with sudo access, its :w can't modify a protected file, but if it passes the buffer contents to the shell, a command in the shell can be run with sudo. In this case, we use tee.

Understanding tee

As for tee, picture the tee command as a T-shaped pipe in a normal bash piping situation: it directs output to specified file(s) and also sends it to standard output, which can be captured by the next piped command.

For example, in ps -ax | tee processes.txt | grep 'foo', the list of processes will be written to a text file and passed along to grep.

     +-----------+    tee     +------------+
     |           |  --------  |            |
     | ps -ax    |  --------  | grep 'foo' |
     |           |     ||     |            |
     +-----------+     ||     +------------+
                       ||   
               +---------------+
               |               |
               | processes.txt |
               |               |
               +---------------+

(Diagram created with Asciiflow.)

See the tee man page for more info.

Tee as a hack

In the situation your question describes, using tee is a hack because we're ignoring half of what it does. sudo tee writes to our file and also sends the buffer contents to standard output, but we ignore standard output. We don't need to pass anything to another piped command in this case; we're just using tee as an alternate way of writing a file and so that we can call it with sudo.

Making this trick easy

You can add this to your .vimrc to make this trick easy-to-use: just type :w!!.

" Allow saving of files as sudo when I forgot to start vim using sudo.
cmap w!! w !sudo tee > /dev/null %

The > /dev/null part explicitly throws away the standard output, since, as I said, we don't need to pass anything to another piped command.

How would I create a text file and fill it with sudo permission in bash

The question has been edited to include a log of the problem being introduced, which includes the command:

# Taken from edited question
$ echo 'hello' > sudo tee /data/hello

In bash (which allows redirection operators at any point in a simple command), this is precisely equivalent to running:

# From question, with redirection moved to end to make actual behavior more readable
echo 'hello' tee /data/hello > sudo

That is, it's creating a file named sudo in your current directory, not using sudo to run tee (in the above, tee is just an argument to echo).

What you want, by contrast, is:

# CORRECT: Using a pipe, not a redirection
echo 'hello' | sudo tee /data/hello

with a pipe (|) rather than a >.

/etc/apt/sources.list E212: Can't open file for writing

Vim has a builtin help system. Running :h E212 inside Vim prints the following:

For some reason the file you are writing to cannot be created or overwritten.
The reason could be that you do not have permission to write in the directory
or the file name is not valid.

You might want to edit the file as a superuser with sudo vim FILE. Or if you don't want to leave your existing vim session (and now have proper sudo rights), you can run:

:w !sudo tee % > /dev/null

Which will save the file.

How to edit a text file in my terminal

Open the file again using vi. and then press the insert button to begin editing it.

How to change file permission from within vi

Just use

:!chmod +w %

in command mode. % will be replaced by the current file name.

---

Related Topics