Configure cron tasks in macOS

Let's assume that you have created a simple script called hello.sh:

bash
echo Hello world >> log.txt

The script prints 'Hello world' and appends it to log.txt.

You can test the script by executing:

terminal
sh hello.sh

At this point you should see a new file called log.txt containing 'Hello world'.

Configure a cron task

To execute the script periodically, for example, one time per day, we can configure a new cron task using the crontab command.

terminal
crontab -e

Type 'A' to edit the file and schedule the script execution time:

terminal
* * * * * [script to execute]
| | | | |
| | | | |__ Weekday (0 - 6) (Sunday = 0)
| | | |____ Month   (1 - 12)
| | |______ Day     (1 - 31)
| |________ Hour    (0 - 23)
|__________ Minute  (0 - 59)

Here is an example on how execute the script one time per day at 14:00:

terminal
0 14 * * * cd /Users/Erik/Desktop && sh hello.sh

Here is another example on how to execute the script one time per minute:

terminal
* * * * * cd /Users/Erik/Desktop && sh hello.sh

Press 'Esc' and type :wq to write and quit.

To check the configured task:

terminal
crontab -l

Allow full access to the disk

At this point, you may need to allow full access to the disk to be able to allow crontab execution.

Go to  > System Preferences > Security & Privacy > Privacy > Full Disk Access. Click on the + button and allow access to usr/sbin/cron.

Note: this configuration may be risky, since now cron tasks have full access to your computer.