A simple elisp tcp daytime server. See RFC 867. Try telnet localhost 10000.
Emacs22 or later (requires server-socket).
(defvar daytime-server-port 10000
"port of the daytime server")
(defun daytime-server-start nil
"starts an emacs daytime server"
(interactive)
(unless (process-status "daytime-server")
(if (featurep 'make-network-process '(:server t))
(make-network-process :name "daytime-server" :buffer "*daytime-server*"
:service daytime-server-port :family 'ipv4 :server t :noquery t
:sentinel nil :filter (lambda (proc string) nil)
:log 'daytime-server-log))))
(defun daytime-server-stop nil
"stop an emacs daytime server"
(interactive)
(delete-process "daytime-server"))
(defun daytime-server-log (server client message)
(process-send-string client (concat (current-time-string) "\n"))
(with-current-buffer "*daytime-server*"
(goto-char (point-max))
(insert (current-time-string)
(format " %s\n" client)))
(delete-process client))