Crontab is used for configuring scheduled tasks on Raspberry Pi. In short, cron is the name of the tool, crontab is the cron table listing the jobs that cron will be executing while these socalled jobs are cronjobs.
How to edit crontab on Raspberry Pi
Run crontab (cron table) with the -e flag to edit the cron table:
crontab -eCrontab commands
crontab -e Edit crontab file (alternatively, create a crontab file if it does not exist).
crontab -l list all crontab jobs.
crontab -r Remove crontab file.
Schedule cronjobs on Raspberry Pi
Cronjobs are created using the following components: minute, hour, day of month, month of year, day of week, as well as the command to be executed.
Graphical Overview
m h dom mon dow command
* * * * * command to execute
┬ ┬ ┬ ┬ ┬
│ │ │ │ │
│ │ │ │ │
│ │ │ │ └───── day of week (0 - 7) (0 to 6 are Sunday to Saturday, or use names; 7 is Sunday, the same as 0)
│ │ │ └────────── month (1 - 12)
│ │ └─────────────── day of month (1 - 31)
│ └──────────────────── hour (0 - 23)
└───────────────────────── min (0 - 59)For example, to execute a command on the 1st of January, June & December at 00:30 – the following will need to be typed in:
min hour day of month month day of week
30 0 1 1,6,12 * Cheatsheet
@hourly - Shorthand for 0 * * * *
@daily - Shorthand for 0 0 * * *
@weekly - Shorthand for 0 0 * * 0
@monthly - Shorthand for 0 0 1 * *
@yearly - Shorthand for 0 0 1 1 *Crontab Format:
MIN HOUR DOM MON DOW CMDFormat Meanings and Allowed Value:
MIN Minute field 0 to 59
HOUR Hour field 0 to 23
DOM Day of Month 1-31
MON Month field 1-12
DOW Day Of Week 0-6
CMD Command Any command to be executed.Examples of Using Cron on Raspberry Pi
How to add apt-update and apt-upgrade as a cronjob on Raspberry Pi
sudo crontab -e
0 3 * * * root /usr/bin/apt-get update && /usr/bin/apt-get upgrade -q -yHow to run script on Raspberry Pi with cronjob
sudo crontab -e
0 0 * * * /home/pi/myscript.shHow to run a cronjob on Raspberry Pi on startup or restart
sudo crontab -e
@reboot /path/to/job
@reboot /path/to/myscript.sh
@reboot /path/to/command argX argYHow to run a cronjob on Raspberry Pi on startup with delay
sudo crontab -e
@reboot sleep 300 && /home/pi/myscript.sh
Thank you for your post.
I installed Nextcloud 23 via docker on a raspberry pi 4 and tried different ways to execute nextcloud’s cron.php file.
crontab -e
*/1 * * * * docker exec -u www-data -it {name or id of container} php cron.php
–> works perfect if I execute it manually
crontab -u www-data -e
*/1 * * * * docker exec -u www-data -it {name or id of container} php cron.php
–> Error: Owner id of config.php: XX
crontab -u pi -e
*/1 * * * * docker exec -u pi -it {name or id of container} php cron.php
–> Error: Owner id of config.php: XX
do you have any idea how to fix it?
Hi Taco,
Did you fix it? Looks like owner issues.
I believe the best course of action would to SSH into your Pi 4 and create:
crontab -e
*/5 * * * * php -f /var/www/nextcloud/cron.php
Note: Replace path if different!
Verify the cron job has been added:
crontab -u www-data -lSource: Nextcloud Background Jobs