The Cron Job/Crontab
To have your task run at this frequency, use the following cron:
30 */12 * * *
This cron command translates to the following (in Human-Readable format):
“Every 12 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 a specific interval. For example, a cron job could be set to run every day at midnight in order to update a database or send out nightly emails. Cron jobs are typically used for maintenance tasks that need to be performed regularly.
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 12 hours at 30 minutes past the hour“:
FUN FACT: One common use for cron jobs is to send out email reminders or notifications based on certain events (such as an upcoming deadline)..
You might want to set up a crontab or cron job to run every 12 hours at 30 minutes past the hour for several reasons, including:
- To send out a daily report at noon and midnight
- To check for new messages every 12 hours
- To refresh data from an external API every 12 hours
- To run a backup script every 12 hours
Similar Cron Jobs
You might also want to run a crontab:
- every 4 hours
- every 1 hour
- every 10 hours
- every 7 hours
- every 11 hours
- every 11 hours at 50 minutes past the hour
- every hour between 12:00 am and 12:00 pm
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 12 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 crontab cheat sheet for a list of hundreds of popular cron jobs.