These notes are not exhaustive. As I learn more I’ll try and update this post.

Cron jobs are useful for running automated tasks in Linux based environments. The syntax is kind goofy and took me reading a few different articles to really grasp it. I found this great article, Writing a basic cron job in Linux which really helped give a good understanding on how the astrisk syntax works.

# ┌───────────── minute (0 - 59)
# │ ┌───────────── hour (0 - 23)
# │ │ ┌───────────── day of the month (1 - 31)
# │ │ │ ┌───────────── month (1 - 12)
# │ │ │ │ ┌───────────── day of the week (0 - 6) (Sunday to Saturday;
# │ │ │ │ │                                   7 is also Sunday on some systems)
# │ │ │ │ │
# │ │ │ │ │
# * * * * *

Resources

• Writing a basic cron job in Linux
• Validate cron jobs
• CronJob

Listing out current cron jobs

Command:

• crontab -l

Compose new cron job

Command:

• crontab -e

You may be asked on the first run which editor to use between Nano and a couple variations of vim.

My uses

I wanted a cron job to run spin up a docker container on my Raspberry Pi at 2pm(PST) Monday - Friday. This seemed like it worked so far, on the first day. 0 14 * * 1,2,3,4,5 docker run [docker image]