How do I open nerdtree in separate window rather than split?

Question

I want to be able to open nerdtree in new window (buffer if you wish) so that it is not in split with the current edited file. The same happens when I open vim from command line with a directory specified as an argument.

Answer 1

You can achieve that with this combination:

:NERDTree | only

Answer 2

"Split" is usually synonymous with "window" and both are not the same as "buffer".

Remove NERDTree from your config, what you want is the normal behavior of the built-in netrw. See :help netrw.

:Ex     " open a listing of the current directory in the current window
:Sex    " open a listing of the current directory in an horizontal window
:Vex    " open a listing of the current directory in a vertical window
:Tex    " open a listing of the current directory in a new tab
:Rex    " go back to the previous listing

$ vim . " open Vim with a listing of the current directory