"In Linux, the crontab command is used to schedule execution of commands at certain time intervals whether it be hourly, daily, monthly or every x amount of minutes. This article is designed to show you the simple way of understanding crontab.
Understanding the fields:
# (Use to post in the top of your crontab)
# ------------- minute (0 - 59)
# | ----------- hour (0 - 23)
# | | --------- day of month (1 - 31)
# | | | ------- month (1 - 12)
# | | | | ----- day of week (0 - 6) (Sunday=0)
# | | | | |
# * * * * * command to be executed