Open files in single emacs instance without daemon.

editor.sh

#!/bin/bash
if pidof emacs &> /dev/null; then
  echo "$1" >> /tmp/emacs-files-to-find
else
  emacs "$1"
fi

open-file-emacs-single-instance.el

(defvar files-to-find-file-name "/tmp/emacs-files-to-find")
(defvar files-to-find-buffer (or (find-buffer-visiting files-to-find-file-name)
                                 (with-current-buffer (find-file-noselect files-to-find-file-name)
                                   (rename-buffer " *emacs-files-to-find-buf*")
                                   (save-buffer)
                                   (current-buffer))))

(defun files-to-find-func-for-hook ()
  (let ((files (split-string
                (with-current-buffer files-to-find-buffer
                  (let ((ret (buffer-string)))
                    (erase-buffer)
                    (save-buffer)
                    ret))
                "\n" t "[ \t\n]")))
    (mapc #'find-file files)))

(with-current-buffer files-to-find-buffer
  (add-hook 'after-revert-hook #'files-to-find-func-for-hook nil t)
  (auto-revert-mode))