Automating recurring tasks with Cron

Setup a crontab file which defines whe the task should run:

m h d M D /script

where:

m minute: 0-59
h hour: 0-23
d day of the month: 1-31
M month of the year: 1-12
D day of the week, Sunday-0, 0-6
/script the script to execute

Values that are not relevant can be replaced with a ‘*” character.

Examples:

Run scriptA at 1:00 am:


* 1 * * * /scriptA

Run scriptB at every 15 minutes past the hour:


15 * * * * /scriptB

Run scriptC on the hour and every 30 minutes past the hour:


0,30 * * * * /scriptC

Run scriptD at 10,11 and 12, every Monday:


* 10-12 * * 1 /scriptC

To install the crontab setings, run:


crontab filename

To list the current crontab settings:


crontab -l

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