The Cron Job/Crontab
To have your task run at this frequency, use the following cron:
30 9 */3 * *
This cron command translates to the following (in Human-Readable format):
“Every 3 days at 9:30 am.”
What is a Cron Job & Crontab?
A cron job is a task that is scheduled to run at a specific time or interval. Cron is a Linux utility that allows tasks to be automatically run in the background at regular intervals. These tasks are often called “cron jobs.”
Crontab files are stored in the “/etc/cron*” directories on most Linux systems. Each user has their own crontab file, and there is also a system-wide crontab file that can be used to schedule system tasks.
Every cron job uses five fields. Here is an explanation of what each field does in this cron, which runs “every 3 days at 9:30 am“:
FUN FACT: When troubleshooting issues with cron jobs, it can be helpful to run them manually from the command line – this will allow you to see any error messages that might be generated..
You might want to set up a crontab or cron job to run every 3 days at 9:30 am for several reasons, including:
- Automatically update software
- Automatically run system maintenance tasks
- Generate daily reports
Similar Cron Jobs
You might also want to run a crontab:
- every 8 days
- every 7 days
- every 6 days
- every 2 days
- every 4 days
- every 9 days
- every 5 days at 6:00 pm
- every 5 days at 12:00 pm
FUN FACT: If you want to edit your personal crontab, just type: “crontab -e” at the command prompt..
In this article, you learned how to set up a cron job that runs every 3 days at 9:30 am. Please share this page with friends and colleagues if you find it useful.
If you have any questions, please don’t hesitate to comment below.
If you are looking for cron jobs that run at certain minutes, hours, days, weekdays, or months, or if you are looking for miscellaneous cron jobs, then check out our relevant sections, or visit our crontab cheat sheet for a list of hundreds of popular cron jobs.