init.el

(defun grep-project (q)
  "Search using git grep"
  (interactive (list
                (read-from-minibuffer "git grep: "
                                      (if (region-active-p)
                                          (buffer-substring-no-properties (region-beginning) (region-end))
                                        (current-word))
                                      nil nil 'grep-project)))
  (let ((command
         (concat
          "cd " (magit-get-top-dir default-directory) " && "
          "git grep --untracked -i -n --no-color --full-name '" q "' -- ")))
    (add-to-history 'grep-find-history command)
    (grep command)
    ))
(setenv "PAGER" "cat")
(global-set-key [(f3)] 'grep-project)