title: E492: Not an editor command: NERDTree
body: <p>When I run <code>vim .</code> to open up a folder I get the following error:</p>
  
  <pre><code>Error detected while processing VimEnter Auto commands for "*":
  E492: Not an editor command: NERDTree .
  Press ENTER or type command to continue
  </code></pre>
  
  <p>I don't understand where this is coming from since everything was working fine. I then tried adding other plugins and then the error was thrown. However I have NERDTree in my <code>~/.vimrc</code> file. Here is what the file looks like.</p>
  
  <pre><code>"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
  let g:plug_shallow = 0 " disable shallow cloning
  
  call plug#begin()
  
  Plug 'airblade/vim-gitgutter'                 " shows a git diff in the gutter
  Plug 'altercation/vim-colors-solarized'       " precision colorscheme
  Plug 'godlygeek/tabular'                      " text filtering and alignment
  Plug 'janko-m/vim-test'                       " test runner
  Plug 'phallstrom/vim-sailfish'
  Plug 'scrooloose/nerdtree'                    " tree explorer
  Plug 'sjl/gundo.vim'                          " graph your vim undo tree
  Plug 'tpope/vim-commentary'                   " comment stuff out
  Plug 'tpope/vim-endwise'                      " wisely add 'end' in ruby, endfunction/endif/more in vim script, etc
  Plug 'tpope/vim-fugitive'                     " git wrapper
  Plug 'tpope/vim-rails', { 'for': ['ruby'] }   " ruby on rails power tools
  Plug 'vim-ruby/vim-ruby', { 'for': ['ruby'] } " vim/ruby configuration
  Plug 'tpope/vim-projectionist'                " project configuration (file jumping)
  Plug 'kana/vim-textobj-user'                  " create your own text objects
  Plug 'nelstrom/vim-textobj-rubyblock'         " custom text object for selecting ruby blocks
  Plug 'tpope/vim-surround'                     " quoting/parenthesizing made simple
  Plug 'chriskempson/base16-vim'                " color schemes, https://chriskempson.github.io/base16/
  Plug 'w0rp/ale'                               " asynchronous lint engine
  Plug 'editorconfig/editorconfig-vim'          " editorConfig plugin
  Plug 'vim-airline/vim-airline'                " status/tabline
  Plug 'vim-airline/vim-airline-themes'         " status/tabline themes
  Plug 'pangloss/vim-javascript'                " Javascript syntax
  Plug 'mxw/vim-jsx'                            " react jsx syntax
  Plug 'posva/vim-vue', { 'for': ['vue'] }      " Vue.js syntax
  Plug '/usr/local/opt/fzf' | Plug 'junegunn/fzf.vim' " A command-line fuzzy finder written in Go
  Plug 'kien/rainbow_parentheses.vim', { 'for': ['clojure'] } " Better Rainbow Parentheses
  Plug 'guns/vim-clojure-static', { 'for': ['clojure'] } " Meikel Brandmeyer's excellent Clojure runtime files
  Plug 'tpope/vim-unimpaired'                   " pairs of handy bracket mappings
  Plug 'tpope/vim-abolish'                      " easily search for, substitute, and abbreviate multiple variants of a word
  Plug 'mechatroner/rainbow_csv'                " highlighting columns in csv/tsv files
  Plug 'slim-template/vim-slim' " slim syntax highlighting for vim
  
  call plug#end()
  """"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
  
  set t_Co=256
  
  set nocompatible      " We're running Vim, not Vi!
  set synmaxcol=500     " don't try to highlight long lines
  compiler ruby         " Enable compiler support for ruby
  
  filetype plugin on
  
  set background=dark
  colorscheme default
  
  set backspace=2
  set expandtab
  set tabstop=2 shiftwidth=2 softtabstop=2
  set autoindent
  set nowrap
  set nrformats=
  
  set backupdir=$HOME/.vimbackup,.
  set directory=$HOME/.vimswap,.
  
  au FocusLost * :wa
  
  set ignorecase
  set smartcase
  set scrolloff=2
  set ttyfast
  set hidden
  set wildmenu
  set wildmode=list:longest
  nnoremap &lt;leader&gt;nt :NERDTreeToggle&lt;enter&gt;
  
  source $VIMRUNTIME/macros/matchit.vim
  
  " fzf
  nnoremap &lt;silent&gt; &lt;C-p&gt; :Files&lt;CR&gt;
  nnoremap &lt;silent&gt; &lt;Leader&gt;b :Buffers&lt;CR&gt;
  
  " https://github.com/tpope/vim-commentary/commit/4dcfc318e0b02fdbb0c2d9ff77cf3562b46eea25
  xmap \\  &lt;Plug&gt;Commentary
  nmap \\  &lt;Plug&gt;Commentary
  
  set updatetime=250
  
  nmap &lt;silent&gt; &lt;leader&gt;s :TestNearest&lt;CR&gt;
  nmap &lt;silent&gt; &lt;leader&gt;t :TestFile&lt;CR&gt;
  nmap &lt;silent&gt; &lt;leader&gt;T :TestSuite&lt;CR&gt;
  
  set mouse=a
  vnoremap &lt;Leader&gt;c "*y
  noremap &lt;Leader&gt;v "*p
  
  set nofixeol
  
  set formatoptions+=j " Delete comment character when joining commented lines
  
  au BufReadPost * if line("'\"") &gt; 0 &amp;&amp; line("'\"") &lt;= line("$") |
      \ exe "normal g'\"" | endif
  
  let g:omni_sql_no_default_maps = 1 " disable SQL autocompletion entirely
  
  " To ensure that EditorConfig plugin works well with Tim Pope's fugitive
  let g:EditorConfig_exclude_patterns = ['fugitive://.*']
  
  " ALE - Asynchronous Lint Engine
  let g:ale_lint_on_enter = 0        " no checks on open
  let g:ale_lint_on_save = 1         " check on save
  let g:ale_lint_on_text_changed = 1 " check on text change
  let g:ale_lint_delay = 300         " millisecond delay before checking
  
  " Airline
  let g:airline_theme = 'base16'                  " theme
  set laststatus=2                                " always show airline
  set noshowmode                                  " hide default mode indicator
  let g:airline_powerline_fonts = 1               " use powerline font
  let g:airline#extensions#wordcount#enabled = 0  " disable word counting
  let g:airline#extensions#whitespace#enabled = 0 " disable detection of whitespace errors
  
  " Rubocop
  let g:vimrubocop_config = '/path/to/rubocop.yml'
  
  if filereadable($HOME."/.vimrc_local")
    source $HOME/.vimrc_local
  endif
  
  let g:jsx_ext_required = 0 " JSX syntax in .js files
  
  " open file splits in vsplit by default
  :nnoremap &lt;C-W&gt;f :vertical wincmd f&lt;CR&gt;
  
  " https://github.com/posva/vim-vue#how-can-i-use-existing-configurationplugins-in-vue-files
  " autocmd BufRead,BufNewFile *.vue setlocal filetype=vue.html.javascript.css
  
  au FileType clojure exe "RainbowParenthesesLoadRound" | RainbowParenthesesActivate
  
  " open NERDTree automatically when vim starts up on opening a directory
  autocmd StdinReadPre * let s:std_in=1
  autocmd VimEnter * if argc() == 1 &amp;&amp; isdirectory(argv()[0]) &amp;&amp; !exists("s:std_in") | exe 'NERDTree' argv()[0] | wincmd p | ene | endif
  
  " https://github.com/slim-template/vim-slim/issues/38#issuecomment-23760100
  autocmd BufNewFile,BufRead *.slim setlocal filetype=slim
  </code></pre>
  
  <p>I re-installed NERDTree but however I still that error.</p>