How do I set the leader key for custom mappings?

Explanation

The leader key is a prefix for custom mappings. Setting it to space makes it ergonomic since space is the largest key on the keyboard.

How it works

• let mapleader = " " sets space as the leader
• Mappings use <leader>: nnoremap <leader>w :w<CR>
• The leader must be set before defining mappings

Example

let mapleader = " "
nnoremap <leader>w :w<CR>       " Space+w saves
nnoremap <leader>q :q<CR>       " Space+q quits
nnoremap <leader>e :e<Space>    " Space+e opens file

Tips

• Space is the most popular leader key choice
• The default leader is \ (backslash)
• <localleader> is for filetype-specific mappings
• :let mapleader must come before any <leader> mappings
• :map <leader> shows all leader mappings