use ag for searching

vimrc

@@ -169,6 +169,9 @@ nnoremap <leader>qfh :chistory<CR>
 nnoremap <leader>qfp :colder<CR>
 nnoremap <leader>qfn :cnewer<CR>
 
+" quick grep of visual selection
+vnoremap <leader>gr y:grep! -R <C-r>" .
+
 " brace/quotes completion
 inoremap {{     {}<left>
 inoremap {{{     {<CR>}<esc>O
@@ -286,6 +289,17 @@ augroup END
 set undodir=/home/ray/.vim/undodir
 set undofile
 
+" Use the silver searcher ag command instead of grep
+if executable('ag')
+  " Use ag over grep
+  set grepprg=ag\ --nogroup\ --nocolor
+
+  " Use ag in CtrlP for listing files. Lightning fast and respects .gitignore
+  let g:ctrlp_user_command = 'ag %s -l --nocolor -g ""'
+
+  " ag is fast enough that CtrlP doesn't need to cache
+  let g:ctrlp_use_caching = 0
+endif
 
 
 " Functions