guile-config/scripts/toggle-tvtime

#!/usr/bin/env guile
!#
;;; toggle-tvtime.scm --- Start or kill tvtime

;; Copyright © 2016 Alex Kost

;; Author: Alex Kost <alezost@gmail.com>
;; Created: 20 Mar 2016

;; This program is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.

;; This program is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with this program.  If not, see <http://www.gnu.org/licenses/>.

;;; Commentary:

;; This script is used to start (with some additional preparations) or
;; kill 'tvtime' if it is already started.

;;; Code:

(use-modules
 (ice-9 match)
 (al display)
 (al processes))

(define (show-help)
  (format #t "Usage: ~a [ARGS ...]
Start tvtime or kill it if already running.
ARGS are arguments passed to tvtime.
"
           (car (command-line))))

(define (run-tvtime)
  (if (getenv "DISPLAY")
      (system* "tvtime")
      (with-display (first-used-display 3)
        (system* "tvtime"))))

(define (main args)
  (match (cdr args)
    (((or "-h" "--help" "help") _ ...)
     (show-help))
    ((args ...)
     (if (process-exists? "tvtime" #:uid (getuid) #:exact? #t)
         (system* "tvtime-command" "QUIT")
         (run-tvtime)))))

(when (batch-mode?)
  (main (command-line)))

;;; toggle-tvtime.scm ends here