The Cron Job/Crontab
To have your task run at this frequency, use the following cron:
0 21-23 * * *
This cron command translates to the following (in Human-Readable format):
“Every hour between 9:00 pm and 11:00 pm.”
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.
A crontab is a table or list of commands that are scheduled to run at specified times. The commands in a crontab file (also called a “cron table”) are normally executed by the cron daemon, which runs in the background and executes these commands automatically.
Every cron job uses five fields. Here is an explanation of what each field does in this cron, which runs “every hour between 9:00 pm and 11:00 pm“:
FUN FACT: When troubleshooting issues with cron jobs, it can be helpful to run them manually from the command line – this will allow you to see any error messages that might be generated..
You might want to set up a crontab or cron job to run every hour between 9:00 pm and 11:00 pm for several reasons, including:
- run a backup
- send out a reminder email
- update statistics
- generate a report
Similar Cron Jobs
You might also want to run a crontab:
- every 10 hours
- every 6 hours
- every 3 hours
- every 5 hours
- every 11 hours
- every hour between 5:00 am and 9:00 pm
- every hour between 9:00 am and 5:00 pm
FUN FACT: Cron jobs can be set up to run at specific times, or they can be configured to run periodically (e.g., every hour)..
In this article, you learned how to set up a cron job that runs every hour between 9:00 pm and 11:00 pm. 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.