" NERDTree shortcut
map <C-n> :NERDTreeToggle<CR>

" open a NERDTree automatically when vim starts up if no files were specified
autocmd StdinReadPre * let s:std_in=1
autocmd VimEnter * if argc() == 0 && !exists("s:std_in") | NERDTree | endif

" close vim if the only window left open is a NERDTree
autocmd bufenter * if (winnr("$") == 1 && exists("b:NERDTreeType") && b:NERDTreeType == "primary") | q | endif