I downloaded and manually installed NERDTree from http://www.vim.org/scripts/script.php?script_id=1658
@hits ➜ .vim rvm:(-ruby-1.9.2) ls -laR
.:
total 28
drwxr-xr-x 6 hitsu hitsu 4096 2012-02-16 15:21 .
drwxr-xr-x 49 hitsu hitsu 4096 2012-02-27 17:43 ..
drwxrwxr-x 2 hitsu hitsu 4096 2011-12-28 14:18 doc
drwxrwxr-x 2 hitsu hitsu 4096 2011-12-28 14:17 nerdtree_plugin
-rw-rw-r-- 1 hitsu hitsu 283 2012-02-07 11:05 .netrwhist
drwxrwxr-x 2 hitsu hitsu 4096 2011-12-28 14:17 plugin
drwxrwxr-x 2 hitsu hitsu 4096 2011-12-28 14:17 syntax
./doc:
total 60
drwxrwxr-x 2 hitsu hitsu 4096 2011-12-28 14:18 .
drwxr-xr-x 6 hitsu hitsu 4096 2012-02-16 15:21 ..
-rw-rw-r-- 1 hitsu hitsu 52744 2011-12-28 14:17 NERD_tree.txt
./nerdtree_plugin:
total 20
drwxrwxr-x 2 hitsu hitsu 4096 2011-12-28 14:17 .
drwxr-xr-x 6 hitsu hitsu 4096 2012-02-16 15:21 ..
-rw-rw-r-- 1 hitsu hitsu 1614 2011-12-28 14:17 exec_menuitem.vim
-rw-rw-r-- 1 hitsu hitsu 8124 2011-12-28 14:17 fs_menu.vim
./plugin:
total 132
drwxrwxr-x 2 hitsu hitsu 4096 2011-12-28 14:17 .
drwxr-xr-x 6 hitsu hitsu 4096 2012-02-16 15:21 ..
-rw-rw-r-- 1 hitsu hitsu 126233 2011-12-28 14:17 NERD_tree.vim
./syntax:
total 12
drwxrwxr-x 2 hitsu hitsu 4096 2011-12-28 14:17 .
drwxr-xr-x 6 hitsu hitsu 4096 2012-02-16 15:21 ..
-rw-rw-r-- 1 hitsu hitsu 3741 2011-12-28 14:17 nerdtree.vim
I tried to open the help file for NERDtree in vim.
However when I typed :helptags I got the error E471: Arugment required
After that I typed :help NERD_tree.txt but I got the error E149: Sorry, can't find help for NERD_tree.txt
Help instructions are taken from: http://www.vim.org/scripts/script.php?script_id=1658
I know that I can just open NERD_tree.txt in any editor manually (for example vim or Emacs), but I'm just asking out of curiosity.
PS I'm a vim noob. :P
You have to give :helptags the directory where the help file (that you want to be parsed) is. For example:
:helptags ~/.vim/doc
I had the same problem, and resolved it with tips from another SO thread:
Apparently you need to :Helptags rather than :helptags
I had the same problem, and specifying the directory for :helptags didn't resolve the problem. It didn't return an error, but it also didn't make :help NERD_tree.txt work. The solution that worked for me was installing pathogen.vim, which is recommended in the NERD Tree installation directions. After I did that, :help NERD_tree.txt worked.
This is an old thread which I stumbeld upon. I will post my workaround anyways. maybe it can be usefull for another one searching like I did.
I opened a terminal in .vim/pack/bundle/start/nerdtree/doc and then started vim.
:helptags .did the trick for me.
来源：https://stackoverflow.com/questions/9468914/vim-helptags-not-working-for-nerdtree