The Cron Job/Crontab
To have your task run at this frequency, use the following cron:
40 */9 * * *
This cron command translates to the following (in Human-Readable format):
“Every 9 hours at 40 minutes past the hour.”
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 typically used for maintenance tasks, such as backing up data or updating software.
Crontab is a file that contains commands and instructions for the cron daemon to execute. The crontab file is usually located in the /etc/cron directory. Each user on a system can have their own crontab file. The commands in the crontab files are executed by the cron daemon at the specified times.
Every cron job uses five fields. Here is an explanation of what each field does in this cron, which runs “every 9 hours at 40 minutes past the hour“:
FUN FACT: Cron jobs can be used to automate just about any task that needs to be performed regularly – so get creative and see what you can come up with!.
You might want to set up a crontab or cron job to run every 9 hours at 40 minutes past the hour for several reasons, including:
- Running a backup of a database
- Checking for updates to software dependencies
- Clearing out old log files
- Sending out nightly emails
Similar Cron Jobs
You might also want to run a crontab:
- every 10 hours
- every 8 hours
- every 7 hours
- every 6 hours
- every 12 hours
- every 7 hours at 10 minutes past the hour
- every hour between 12:00 pm and 7:00 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 9 hours at 40 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.