The Cron Job/Crontab
To have your task run at this frequency, use the following cron:
30 */8 * * *
This cron command translates to the following (in Human-Readable format):
“Every 8 hours at 30 minutes past the hour.”
What is a Cron Job & Crontab?
A cron job is a Linux utility used for scheduling the execution of commands or scripts at a specified time and date. Cron is typically used for system maintenance or administration, such as running backups or log rotation.
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 8 hours at 30 minutes past the hour“:
FUN FACT: Cron jobs are named after the Greek god of time, Chronos – so now you know where the name comes from!.
You might want to set up a crontab or cron job to run every 8 hours at 30 minutes past the hour for several reasons, including:
- Sending out a daily email report
- Generating a report of website statistics
- Checking for new software updates
- Downloading new data from an API
Similar Cron Jobs
You might also want to run a crontab:
- every 7 hours
- every 3 hours
- every 11 hours
- every 6 hours
- every 10 hours
- every 12 hours
- every hour between 3:00 am and 12:00 pm
- every hour between 10:00 pm and 11:00 pm
- every 4 hours at 30 minutes past the hour
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 8 hours at 30 minutes past the hour. 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.