The Cron Job/Crontab
To have your task run at this frequency, use the following cron:
30 8 */4 * *
This cron command translates to the following (in Human-Readable format):
“Every 4 days at 8:30 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 jobs are commonly used to automate system maintenance or administration tasks, such as running backups or sending emails.
A crontab is a file that contains a list of commands that are to be executed at specified times. The commands in the crontab are executed by the cron daemon, which runs in the background.
Every cron job uses five fields. Here is an explanation of what each field does in this cron, which runs “every 4 days at 8:30 am“:
FUN FACT: Cron is one of the most versatile tools in a Linux administrator’s toolbox..
You might want to set up a crontab or cron job to run every 4 days at 8:30 am for several reasons, including:
- Sending a daily digest email to subscribers
- Generating a report of activity for the past 4 days
- Checking for updates to a remote data source
Similar Cron Jobs
You might also want to run a crontab:
- every 1 day
- every 4 days
- every 7 days
- every 6 days
- every 3 days
- every 10 days
- every 9 days at 3:00 pm
- every 9 days at 2:30 pm
FUN FACT: Each user on a system can have their own crontab, and commands in them will be executed as that user..
In this article, you learned how to set up a cron job that runs every 4 days at 8:30 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.