The Cron Job/Crontab
To have your task run at this frequency, use the following cron:
1 */3 * * *
This cron command translates to the following (in Human-Readable format):
“Every 3 hours at 1 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. These jobs are usually used for maintenance or automation purposes. For example, a cron job could be set to delete temporary files every week so that they don’t take up space on the server.
Crontab is a file that contains instructions for the cron daemon, which is a program that executes commands at specified intervals. Crontab files are typically edited with the crontab command, which allows users to create, edit, and delete their own crontab files.
Every cron job uses five fields. Here is an explanation of what each field does in this cron, which runs “every 3 hours at 1 minutes past the hour“:
FUN FACT: Cron jobs are named after the Greek god Chronos, who represents time itself..
You might want to set up a crontab or cron job to run every 3 hours at 1 minutes past the hour for several reasons, including:
- Check for updates to a software repository
- Run a script to update data in a database
- Delete old files from a temporary directory
- Generate reports based on log file data
Similar Cron Jobs
You might also want to run a crontab:
- every 10 hours
- every 12 hours
- every 2 hours
- every 5 hours
- every 3 hours
- every hour between 1:00 pm and 11:00 pm
- every 1 hour at 30 minutes past the hour
- every 11 hours at 20 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 3 hours at 1 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.