The Cron Job/Crontab
To have your task run at this frequency, use the following cron:
30 */4 * * *
This cron command translates to the following (in Human-Readable format):
“Every 4 hours at 30 minutes past the hour.”
What is a Cron Job & Crontab?
A cron job is a scheduled task that is typically executed by the operating system on a regular basis. Cron jobs are often used to perform maintenance or administrative tasks, such as backing up data or updating software.
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 4 hours at 30 minutes past the hour“:
FUN FACT: Cron jobs are often used to perform regular maintenance tasks, such as running backups or sending out reports..
You might want to set up a crontab or cron job to run every 4 hours at 30 minutes past the hour for several reasons, including:
- Sending a daily report on server usage
- Archiving old log files
- Generating monthly sales reports
- Calculating weekly payroll
Similar Cron Jobs
You might also want to run a crontab:
- every 10 hours
- every 6 hours
- every 7 hours
- every 4 hours
- every 1 hour at 20 minutes past the hour
- every hour between 1:00 am and 2:00 am
- every hour between 4:00 am and 11:00 pm
FUN FACT: The most common way to edit cron jobs is using the crontab command – this stands for “cron table,” and it contains all the information about when your tasks should be executed..
In this article, you learned how to set up a cron job that runs every 4 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.