The Cron Job/Crontab
To have your task run at this frequency, use the following cron:
30 3 */4 * *
This cron command translates to the following (in Human-Readable format):
“Every 4 days at 3:30 am.”
What is a Cron Job & Crontab?
A cron job is a time-based task that is set to run at a specific time or interval. These jobs are usually used for automating tasks, such as running backups or sending emails. Cron is the name of the program that enables users to schedule these jobs.
A crontab is a file containing commands and instructions for the cron daemon to execute. The crontab is used to schedule jobs (commands or shell scripts) to run periodically at certain times or dates.
Every cron job uses five fields. Here is an explanation of what each field does in this cron, which runs “every 4 days at 3:30 am“:
FUN FACT: Cron is one of the most powerful tools available on a Linux system – use it wisely!.
You might want to set up a crontab or cron job to run every 4 days at 3:30 am for several reasons, including:
- A daily backup script
- A security scan
- Sending out a daily newsletter
- Generating reports
Similar Cron Jobs
You might also want to run a crontab:
- every 6 days
- every 1 day
- every 5 days
- every 9 days
- every 8 days
- every 3 days
- every 7 days at 7:30 am
- every 3 days at 11:30 am
FUN FACT: A common use for cron jobs is to generate periodic reports – for example, you could set up a cron job to automatically generate and send out a report on website traffic statistics every week..
In this article, you learned how to set up a cron job that runs every 4 days at 3:30 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 cron job cheat sheet for a list of hundreds of popular cron jobs.