cron is a job scheduler that runs predefined commands at a preset time.

To edit the list of cron jobs, run crontab -e in console.

#  .---------------- minute
#  |  .------------- hour
#  |  |  .---------- day
#  |  |  |  .------- month 
#  |  |  |  |  .---- day of week (0-7 or sun,mon,tue,wed,thu,fri,sat)
#  |  |  |  |  |     command
#
#  *  *  *  *  *     /path/to/script -foo -bar

Each job is defined as a line of parameters where

• minute is a number from 0to 59, or a period (e.g. */10 for every 10 minutes).
• hour is a humber from 0 to 23.
• day is the day of the month, a number from 1 to 31.
• month is a number from 1 to 12, or a three-letter abbreviation: jan, feb, mar, apr, may, jun, jul, aug, sep, nov, dec.
• day of week is a number from 0 (for Sunday) to 7 (for Sunday again).
• command is a path to the script to be executed, with optional arguments.