The Cron Job/Crontab
To have your task run at this frequency, use the following cron:
0 0 */3 * *
This cron command translates to the following (in Human-Readable format):
“Every 3 days.”
What is a Cron Job & Crontab?
A cron job is a task that is scheduled to run at a specified 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 table or list of commands that are scheduled to run at specified times. The commands in a crontab file (also called a “cron table”) are normally executed by the cron daemon, which runs in the background and executes these commands automatically.
Every cron job uses five fields. Here is an explanation of what each field does in this cron, which runs “every 3 days“:
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..
You might want to set up a crontab or cron job to run every 3 days for several reasons, including:
- A daily backup that needs to run every 3 days
- Checking for updates to a software package that need to be installed every 3 days
- Running a script to generate reports every 3 days
Similar Cron Jobs
You might also want to run a crontab:
- every 9 days
- every 4 days
- every 2 days
- every 10 days
- every 1 day
- every 6 days
- every 9 days at 5:00 pm
- every 3 days at 9:00 am
- every 5 days at 2:30 am
FUN FACT: Cron jobs are named after the Greek god of time, Chronos – so now you know where the name comes from!.
In this article, you learned how to set up a cron job that runs every 3 days. 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.