* | any value |

, | value list separator |

- | range of values |

/ | step values |

### How to run crontab every 21 minutes?

Cronjob is a fantastic feature, that enables you to schedule your repetitive jobs. */21 * * * * let's you run a script/program every 21 minutes. All you need to do is, configure this cronjob in your system with the script/program you want to run, which can be done in an unix/linux based operating system as following:

Step 1: Edit your cronjob file by running "crontab -e" command

Step 2: Add the following line for every 21 minutes interval:

*/21 * * * * /path/to/your/script-or-program

Step 3: Save the file. That's it!### How to run a script in crontab every 21 minutes?

Cronjob let's you run a script to do a repetitive job in an efficent way, here's how you can schedule a cronjob for every 21 minutes:

Step 1: Edit your cronjob file by running "crontab -e" command

Step 2) Add the following line for every 21 minutes interval:

*/21 * * * * /path/to/your/script

Step 3: Save the file. That's it!### Is */21 * * * * the right expression for every 21 minutes?

Absolutely, this is the correct expression for the magic you are looking for. */21 * * * * let's you run a cronjob every 21 minutes.

### What are some examples of every 21 minutes crontab?

There are potentially infinte examples for it. Think about any job that you want to run every 21 minutes, it can be processing some data, generating a report, crawling an external source, pinging another service etc.

For example, if I want to check uptime of my website in every 1 minute, I can write a program to do this for me using this powerful functionality of scheduling.

- every 10 minutes
- every 5 minutes
- every minute
- every 2 minutes
- every 3 minutes
- every 4 minutes
- every 15 minutes
- every 30 minutes
- every 12 hours
- every week
- monday to friday
- every year
- every 6 month
- every quarter
- once a month
- every friday
- every thursday
- every saturday
- every 45 minutes
- every 50 minutes
- every 40 minutes
- every 21 minutes
- every 17 minutes
- every 19 minutes
- every 11 minutes
- every hour
- every 2 hours
- every 3 hours
- every 4 hours
- every 5 hours
- every 6 hours
- twice a day
- 3 times a day
- every day of week
- every 7 days
- every 10 days
- every 90 days
- every 15 days
- every 30 days
- every monday
- every tuesday
- every wednesday
- every sunday
- first Day of Month