cron field

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# Cron Usage
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# ATFT, You do it! Hit your console (man 5 crontab)
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# You don't hope to get the mail.
# MAILTO="" or MAILTO=''
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# You hope to send the mail to the group of people.
# MAILTO=user1,user2,user3,-------,userx
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# +---------------- minute (0 - 59)
# | +------------- hour (0 - 23)
# | | +---------- day of month (1 - 31)
# | | | +------- month (1 - 12)
# | | | | +---- day of week (0 - 6) (Sunday=0 or 7)
# | | | | |
# * * * * * command to be executed