Saving a read-only file in vi.

Oops

Let’s say that you’ve just finished a long edit of a read-only config file as a regular user. You forgot to open the file with elevated privileges. What do you do? Thankfully, vi allows users to run UNIX commands without having to exit the program:

:w !sudo tee %

Here’s a quick breakdown of the above command:

1. : tells vi that you’d like to issue a command.
2. w tells vi to write the current file.
3. ! tells vi to expect a shell command to follow.
4. tee is a shell command to copy from standard input and write to standard output.
5. % tells vi to use the current file name.

As an aside, you may also be interested to note that you can open a shell prompt from within vi by running :sh. vi will use whatever is returned by echo $SHELL.