Answers:
使emacs的窗口标题显示当前文件的路径:
(setq-default frame-title-format
'(:eval
(format "%s@%s: %s %s"
(or (file-remote-p default-directory 'user)
user-real-login-name)
(or (file-remote-p default-directory 'host)
system-name)
(buffer-name)
(cond
(buffer-file-truename
(concat "(" buffer-file-truename ")"))
(dired-directory
(concat "{" dired-directory "}"))
(t
"[no file]")))))