The Cron Job/Crontab
To have your task run at this frequency, use the following cron:
0 0 21 * *
This cron command translates to the following (in Human-Readable format):
“Every 1 month on day 21 of the month.”
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 system maintenance or administration tasks, such as backing up data or updating software.
Crontab files are stored in the “/etc/cron*” directories on most Linux systems. Each user has their own crontab file, and there is also a system-wide crontab file that can be used to schedule system tasks.
Every cron job uses five fields. Here is an explanation of what each field does in this cron, which runs “every 1 month on day 21 of the month“:
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 1 month on day 21 of the month for several reasons, including:
- To send a monthly report on the 21st of every month
- To run a script to check for updates on the 21st of every month
- To delete old log files on the 21st of every month
Similar Cron Jobs
You might also want to run a crontab:
- every 2 months
- every 6 months
- every 1 month
- every 5 months
- every 3 months
- every 1 month on day 17 of the month
- every 4 months on day 22 of the month
FUN FACT: Cron jobs are named after the Greek god Chronos, who represents time itself..
In this article, you learned how to set up a cron job that runs every 1 month on day 21 of the month. 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.