Error “E212: Can’t open file for writing” in Vim
To save that file run:
:w !sudo tee % > /dev/null
File is saved.
Next time you edit a config file run:
$ sudo vi file
Also, remember Vim has a builtin help system. Running
:h E212 will show:
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.