Sometimes when editing a configuration you may find out that the file you opened was opened as ‘sudo’ hence you won’t be able to save it.
There is a solution to it so you don’t have to lose the configuration you have already done.
:w !sudo tee %
% means the current file
:w is saving the buffer not a current file, so if you type type in :w !sudo tee test2.txt ,this would save the buffer in the new test2.txt file instead of the current opened file.