The Cron Job/Crontab
To have your task run at this frequency, use the following cron:
30 */6 * * *
This cron command translates to the following (in Human-Readable format):
“Every 6 hours at 30 minutes past the hour.”
What is a Cron Job & Crontab?
A cron job is a time-based task that is set to run at specific intervals. This can be anything from running a backup script every night to sending out an email notification once a week. Cron jobs are typically used for maintenance or repetitive tasks.
A crontab is a file that contains a list of commands that are to be executed at specified times. The commands in the crontab are executed by the cron daemon.
Every cron job uses five fields. Here is an explanation of what each field does in this cron, which runs “every 6 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 6 hours at 30 minutes past the hour for several reasons, including:
- To run a backup of all user data once every 6 hours
- To send out a notification to all users every 6 hours
- To check for new updates to the software once every 6 hours
Similar Cron Jobs
You might also want to run a crontab:
- every 11 hours
- every 4 hours
- every 1 hour
- every 8 hours
- every hour between 10:00 am and 8:00 pm
- every hour between 5:00 am and 1:00 pm
FUN FACT: Cron is one of the most powerful tools available on a Linux system – use it wisely!.
In this article, you learned how to set up a cron job that runs every 6 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 cron job cheat sheet for a list of hundreds of popular cron jobs.