How to change file permission from within vi

Question

I sometimes open a read-only file in vi, forgetting to do chmod +w before opening it. Is there way to change the file from within vi?

Something like !

Answer 1

If you have the rights to write to the file, then you can just use exclamation mark to force it:

:w!

If you don't have the rights and need to change user, but still want to write to the file, sometimes you may go for something like

:w !sudo tee %