Debian crontab

The crontab is a built-in Linux scheduling tool that lets you run commands and scripts automatically at any time or interval without any manual interaction. It works on top of the crond daemon, which runs continuously in the background and checks every minute whether any scheduled jobs are due to execute. System administrators use crontab to automate routine tasks like backups, log rotation, disk cleanup, and remote syncing.

This guide covers the crontab syntax for Debian 12, provides 12 practical examples from running scripts at midnight to backing up directories on a weekly schedule, and explains how to list, create, and remove cron jobs for any user. Many system-level cron jobs require sudo access on Debian 12 to execute correctly.

Quick Answer

Open the crontab editor with:

crontab -e

Add a line using this format, then save with Ctrl + S and exit with Ctrl + X:

[Minute] [Hour] [Day of month] [Month] [Day of week] /path/to/script.sh

Use * as a wildcard for any value. For example, 0 3 * * * /backup.sh runs the script every day at 3 AM.

Understanding the crontab Syntax

The crontab file stores scheduled jobs, one per line. Open it with crontab -e, which creates it if no file exists yet for the current user:

crontab -e

Debian crontab file open in editor after running crontab -e showing the default template with comment lines

Each line follows this format:

[Minute] [Hour] [Day (of the month)] [Month (of the year)] [Day (of the week)] [path_to_script_or_command]

The five time fields accept numbers, ranges like 1-5, comma-separated lists like 1,3,5, step values like */5, or * as a wildcard meaning every unit. All configurations are stored in /tmp/crontab.random/crontab for the current user.

How to Use Debian crontab

Example 1: Save the Date and Time on Every Reboot

Use the @reboot shortcut to run a command each time the system boots. This example appends the current date and time to a file called date.txt in the home directory:

@reboot date >> ~/date.txt

Crontab file showing @reboot date data-lazy-src=

To delay startup execution, add a sleep before the script:

@reboot sleep 600 && /path/to/script.sh

Save changes with Ctrl + S and exit the editor with Ctrl + X.

Example 2: Run a Script on a Fixed Schedule

Five asterisks run a script every minute. Replace the path with the actual path to your script:

* * * * * /path-to-script

Crontab file showing * * * * * /path-to-script entry running a script every minute on Debian 12

Each field position controls a different time unit:

First *	Minutes (0-59)
Second *	Hours (0-23, 24-hour notation)
Third *	Day of the month (1-31)
Fourth *	Month of the year (1-12)
Fifth *	Day of the week (0-7, where 0 and 7 both mean Sunday)

Example 3: Run a Script Every Five Minutes

Setting the minute field to 5 runs the job at minute 5 of every hour. To run truly every five minutes, use the step syntax */5 in the minute field instead:

5 * * * * /home/user/script.sh

Crontab file showing 5 * * * * /home/user/script.sh running the script at minute 5 of every hour on Debian

Example 4: Run a Script at Midnight

Set both the minute and hour fields to 0 to run at exactly midnight. You can also use @daily or @midnight as shortcuts, both of which are equivalent to 0 0 * * *:

0 0 * * * /home/user/script.sh

Crontab file showing 0 0 * * * /home/user/script.sh scheduled to run a script at midnight every day

@daily /path-to-script

Example 5: Run a Script on the First of Every Month

Set the day-of-month field to 1 to run at midnight on the first of each month. This is useful for automating monthly reports, billing jobs, or log archiving. Use @monthly as a shortcut:

0 0 1 * * /home/user/script.sh

Crontab file showing 0 0 1 * * /home/user/script.sh running a script on the first day of each month

@monthly /home/user/script.sh

Example 6: Run a Script Yearly

Use 0 0 1 1 * to run a script at midnight on January 1st each year. Use the @yearly shortcut for the same result:

0 0 1 1 * /home/user/script.sh

Crontab file showing 0 0 1 1 * /home/user/script.sh running a script on January 1st at midnight each year

@yearly /home/user/script.sh

Example 7: Run Multiple Cron Jobs at Once

Separate multiple commands with a semicolon on the same schedule line to run them together at the specified time:

* * * * * /path-to-script1.sh; /path-to-script2.sh

Crontab file showing two scripts separated by a semicolon on one line to run as multiple simultaneous cron jobs

Example 8: Run a Script Every Hour on Weekdays

Use a range in the hour field and the day-of-week field to run a script every hour between 9 AM and 5 PM, Monday through Friday. The range 9-17 covers 9 AM to 5 PM in 24-hour notation, and 1-5 covers Monday to Friday:

0 9-17 * * 1-5 /home/user/script.sh

Example 9: Sync a Remote Directory at a Specific Time

Use rsync in a crontab job to automatically sync a local directory to a remote server each night at 1 AM. Configure SSH key-based authentication first so rsync can connect without being prompted for a password:

0 1 * * * rsync -a /local/directory/ Remote-User@IP:/remote/directory/

Crontab file showing rsync command scheduled at 1 AM daily to sync a local directory with a remote server

Example 10: Delete Temporary Files Every Night

Temporary files accumulate over time and consume disk space. Although the system clears some on reboot, others persist. This cron job removes everything in /tmp every night at 1 AM:

0 1 * * * rm -rf /tmp/*

Crontab file showing 0 1 * * * rm -rf /tmp/* scheduled to delete temporary files every night at 1 AM on Debian

Example 11: Monitor Disk Usage Every Hour

Log disk usage statistics to a file every hour using the df command. This builds a historical record you can review to track storage trends and spot problems before they become critical:

0 * * * * df -h >> ~/disk.txt

Crontab file showing 0 * * * * df -h data-lazy-src=

View the collected output with:

cat disk.txt

Terminal showing cat disk.txt output with hourly disk usage statistics captured by the crontab job on Debian 12

Example 12: Back Up a Directory on a Weekly Schedule

Create a timestamped tar archive of a directory every Sunday between 4 AM and 6 AM. You can adapt this to back up any folder, including VirtualBox virtual machine directories or important home folders:

0 4-6 * * 0 tar -czf /path/to/backup_$(date +%Y-%m-%d).tar.gz /path/to/directory

Crontab file showing tar backup command scheduled to run every Sunday between 4 AM and 6 AM on Debian 12

Useful crontab Commands

List All Cron Jobs

View all scheduled cron jobs for the currently logged-in user:

crontab -l

Debian terminal showing crontab -l output listing all scheduled cron jobs for the current user

Manage Another User’s Cron Jobs

A user with sudo access on Debian 12 can view and create cron jobs for other users. Replace test with the target username:

sudo crontab -u test -l

crontab -u <username> -e

Remove Active Cron Jobs

Delete all cron jobs for the current user:

crontab -r

Debian terminal showing crontab -r command removing all active cron jobs for the current user

To remove cron jobs for another user, use the -u flag with sudo:

sudo crontab -u test -r

Debian terminal showing sudo crontab -u test -r command deleting all cron jobs for another specified user

To automate software builds and deployments on a schedule, see how to build a Debian package.