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The Vim Trick Which Will Save Your Time and Nerves

jovica on September 11, 2018

Whether you're beginner or advanced Vim user, I'm sure you've seen this at least once: E45: 'readonly' option is set (add ! to override) ...

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Braden Best • Sep 11 '18 • Edited

I just use :w !sudo tee % when that happens. I don't come across that situation enough to justify a mapping, and the command is easy to reinvent when needed.

w <file> writes to a file, and can be redirected to an external program's stdin if file is !<command>

sudo tee <file> takes its input and writes it to both stdout and file.

% is vim shorthand for the file open in this buffer.

Btw: sudo -e some_file. Try it.

tux0r • Sep 11 '18

the magic trick which would take another post to explain

Here's a comment to save you another post:

! executes a command and returns its result. This was adopted from Vim's predecessors, it already exists in ed (which begat em which begat en which begat ex which begat vi which was cloned as stevie which begat Vim, eventually).
tee splits the input (here: the contents of the buffer which is % in Vim's language) into an output file (redirected into the void, >/dev/null) and an output stream (returned).
write is the equivalent to :w.

Wouldn't /dev/zero be faster, by the way?

jovica • Sep 11 '18

hah - thanks :) It's just hardly understandable for beginners in this kind of short form - that's what I had in mind when I mentioned another post.

I didn't test the difference between the /dev/zero and /dev/null, but it shouldn't make a really big difference in this case. Cheers!

Michael Mior • Sep 18 '18

At least on my machine, /dev/zero and /dev/null are the same speed. Even if they were different, I doubt it would be enough to matter unless you were writing a really massive file.

Supahambition • Sep 11 '18

Or use the chmod command to change the permissions of the file right?
Idk about you guys but I'm not particularly comfortable with running vim through Super User all the time. But maybe that's just being paranoid?

jdnewman85 • Sep 11 '18

This 'trick' alleviates the need to run vim itself as root. Changing permissions is not always preferable. How do you edit system configs? Full blown root user?

Your paranoia has caused you to be less safe...

Ítalo Vieira • Jul 6 '19 • Edited

sudoedit (or sudo -e) is the right way to do when you have not yet open the file with Vim.

vinney cavallo • Sep 11 '18

Sometimes you want the permissions staying the same, but you need the file changed regardless. Maybe this is bad practice, I dunno. Would be curious to hear it discussed by folks who know more than I do.

Sam Yi • Sep 12 '18

Man though crowd. I like this shortcut. Thanks for posting.

jovica • Sep 14 '18

Haha, thanks :)

Kevin Cui • Sep 11 '18

Nice trick! Unfortunately, at this moment it's not working in Neovim. I have to use a plugin instead github.com/lambdalisue/suda.vim

Gnu's Not Unix • Sep 17 '18 • Edited

I use this map:

cnoremap WW w !sudo tee > /dev/null %

However, I prefer to edit files with this alias:

alias svim='sudoedit'

David Castro • Sep 18 '18

Just a warning for anyone that uses this, sudoedit or sudo -e makes a temporary copy of the file and then moves it on top of the real file when the editor exits. Which means that writing your changes doesn't actually modify the file, which caused me much head banging because no matter what I did I'd get the same error since I was making changes that were buffered in sudoedit until I closed my editor, but I was retrying after just writing the change.