Is there a way to periodically run an elisp function in a long-running emacs, similar to cron, but within the emacs process?
For example I want to "automatically run (recentf-save-list) every half hour" because it otherwise only runs on exit, which sucks when emacs occasionally crashes. (There are other examples as well so looking for a general solution rather than one in particular for recentf).
Check out run-with-timer.
(run-with-timer 0 (* 30 60) 'recentf-save-list)
You might also find midnight mode useful. One can arbitrarily define 'midnight' and then add hooks as desired.
来源：https://stackoverflow.com/questions/3841459/how-to-periodically-run-a-task-within-emacs