How do I use the command key in MacVim? For example I would like to be able to press Cmdt to open CtrlP or Cmdn to open NerdTree.
See :help <D-. Use <D-t> to map to ⌘-T; however, ⌘-T is already mapped to "New Tab" within MacVim's menu. You'll have to remove that to be able to use it in a Vim map.
Some keys are OS-bound and you just can't access them, but ⌘-T can be made available and is actually the example they use in the help file (see :help Actions.plist and scroll up a few lines to 4.). You'll need to unset the "New Tab" binding with
:macmenu File.New\ Tab key=<nop>
and then map ⌘-T with nnoremap <D-t> whatever.
The command key on OS X is known as the Super key in Vim, so you can do the following:
map <D-t> :CtrlP<CR>
map <D-n> :NERDtree<CR>
You can read more about the different key mappings in :help key-notation. You can't use the command key as a leader because it doesn't lead off a command, but is instead a modifier.
来源：https://stackoverflow.com/questions/11979313/command-key-in-macvim