reminder.py

import sched, time, sys
from pync import Notifier

try:
    seconds = int(sys.argv[1])*60
    text = sys.argv[2]

    def showNotifier():
            Notifier.notify(text, title="Reminder", sound="default")


    def setReminder():
        s = sched.scheduler(time.time, time.sleep)

        s.enter(seconds, 1, showNotifier, ())
        s.run()


    setReminder()

except IndexError:
    print 'ops, no parameters specified'

pip install pync

python remainder.py 10 "remember the milk" &