Crontab format

*     *     *     *     *  command to be executed
-     -     -     -     -
|     |     |     |     |
|     |     |     |     ------ day of week (0 - 6) (Sunday=0)
|     |     |     -------- month (1 - 12)
|     |     ---------- day of month (1 - 31)
|     ------------ hour (0 - 23)
------------- min (0 - 59)