How can I start vim and then execute a particular command that includes a \, from the command line?

Question

In my ~/.vimrc, I have a command defined approximately like this:

nnoremap <expr> <Leader>n ':new ~/Notes/' . strftime('%F') . '-'

It is designed for creating notes files that contain the current date in the filename. The keybinding is designed to leave my cursor on the command line so that I can type the topic of the note and hit Return.

This works from within vim fine. However, I am also trying to specify a terminal command that I can use to open vim and then fire this command. I've tried:

vim -c '\n'

(my Leader is set to the default of \, which I would prefer not to change)

However, this doesn't work - instead I just get Error detected while processing command line: E10: \ should be followed by /, ? or &. I'm not sure if this is a bug in vim or if I'm doing something wrong. I also tried:

vim -c '<Leader>n'

But this gives: Error detected while processing command line: E488: Trailing characters: n Press ENTER or type command to continue.

Is there a way to achieve what I want?

Answer 1

You could make a function that creates the new entry, and then use the function as part of your mapping:

nnoremap <leader>t :call NewEntry()<cr>
function! NewEntry()
  let title = expand('~/Notes/') . strftime('%F') . '-' . input("Title: ")
  execute 'edit ' . title
endfunction

The mapping may be called as described by @Carpetsmoker:

vim -c 'execute "normal \\t"'

Answer 2

-c doesn't execute keybinds in normal mode; it executes commands (what you normally do with :). So you need to use the execute command, which seems to work:

$ vim -c 'execute "normal \\t"'

We need the double \\ because we're issuing a shell command (and don't want the shell to interpret this as an escape sequence).

Tested with the keybind:

nnoremap <Leader>t :echo "TEST!"<CR>

I can't get :execute "normal <Leader>t" to work; getting the value of mapleader is also slightly more involved since you get an error if you didn't set mapleader to anything and use the default of \.

Answer 3

If your goal is to use mapleader and you have it redefined in your .vimrc

let mapleader = ','

that wouldn't work. You can use

$ vim -c 'execute "normal ".get(g:,"mapleader","\\")."t"'

instead.

but if you plan to use that functionality from command line, is better to encapsulate functionality on a function and call it directly.