The Cron Job/Crontab
To have your task run at this frequency, use the following cron:
30 */9 * * *
This cron command translates to the following (in Human-Readable format):
“Every 9 hours at 30 minutes past the hour.”
What is a Cron Job & Crontab?
In computing, a cron job is a time-based task that is set to run at certain predetermined times or intervals. A cron job can be used to schedule anything from basic tasks like running backups to more complex tasks like sending out email alerts or syncing files between servers. Cron jobs are typically used for maintenance or administrative tasks that need to be performed on a regular basis.
A crontab is a file that contains instructions for the cron daemon. The cron daemon is a program that runs in the background and executes tasks at specified times. A crontab file typically contains a list of commands, with each command being executed at a specified time.
Every cron job uses five fields. Here is an explanation of what each field does in this cron, which runs “every 9 hours at 30 minutes past the hour“:
FUN FACT: If you want to see what commands are scheduled in your crontab, type: “crontab -l”.
You might want to set up a crontab or cron job to run every 9 hours at 30 minutes past the hour for several reasons, including:
- Automated backups
- Checking for system updates
- Generating reports
- Running a maintenance script
Similar Cron Jobs
You might also want to run a crontab:
- every 3 hours
- every 10 hours
- every 4 hours
- every 1 hour
- every 5 hours
- every 5 hours at 40 minutes past the hour
- every hour between 12:00 am and 10:00 am
- every hour between 1:00 pm and 4:00 pm
FUN FACT: Cron jobs are often used to perform regular maintenance tasks, such as running backups or sending out reports..
In this article, you learned how to set up a cron job that runs every 9 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.