Setting Up a Cron Job

Setting Cron to run on Mac Os

• Cron needs full disk access in order to run on mac
• Go to System Settings > Privacy & Security > Full Disk Access:
• Click on the (+) icon to add an item to the list.
• Press command+shift+G, type /usr/sbin/cron and press enter:
• Select the cron executable and click Open

Vim Editor Commands

shift + :

• :i // insert text
• esc key // get out of insert mode
• :wq Write file to disk and quit the editor
• :q! Quit without saving

Setting up a Cron Job

crontab -e  # use the -e switch, do not edit the file directly 
crontab -l # shows scheduled jobs
crontab -r  # remove the current crontab file

Crontab sections

Parts of cron tab

Minute	Hour	Day (month)	Month	Day (week)
*	*	*	*	*
0-59	0-23	1-31	1-12 or jan, feb,mar,..	0-6 or sun, mon, tue

Every Minute	* * * * *	Ever 5 Minute	*/5 * * * *	Ever 30 Minutes	*/30 * * * *
Every Hour	0 * * * *	Every Hour and 30 min	30 * * * *	Ever 2 hours	0 */2 * * *

• minute of the hour the command will run on, and is between '0' and '59'
• hour the command will run on, and is specified in the 24 hour clock, values must be between 0 and 23 (0 is midnight)
• Day of Month, that you want the command run on, e.g. to run a command on the 19th of each month, the dom would be 19.
• month a specified command will run on, it may be specified numerically (0-12), or as the name of the month (e.g. May)
• the Day of Week that you want a command to be run on, it can also be numeric (0-7) or as the name of the day (e.g. sun).
• user who runs the command.
• command that you want run. This field may contain multiple words or spaces.

* 12 10-16/2 * * /scripts/backup.sh

When using the names of weekdays or months, it isn't case sensitive, but only the first three letters should be used, e.g. Mon, sun or Mar, jul.

Comments are allowed in crontabs, but they must be preceded with a '#', and must be on a line by them self.

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