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Cron Jobs

Cron Jobs allow you to schedule commands or scripts to run automatically at defined intervals.
They are a core part of system automation and maintenance in the OS.

Cron Jobs are commonly used for:

• System maintenance tasks
• Scheduled backups
• Log rotation and cleanup
• Monitoring and health checks
• Custom automation scripts

The Cron Jobs menu is located under:

Settings → System Configuration → Cron Jobs

Here you can create new cron jobs and manage existing ones.

Example:

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Creating a New Cron Job

To create a new cron job, click the Plus Icon and fill in the required fields.

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Cron Job Configuration Fields

Name

Defines the name of the cron job.

Best practice:

• Use clear and descriptive names
• Avoid spaces and special characters
• Reflect the purpose of the job

Examples:

• daily_backup
• log_cleanup
• update_check
• media_rescan

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Schedule

Defines when and how often the cron job is executed.

The schedule follows standard cron syntax.

Format:

minute hour day month weekday

Examples:

• 0 2 * * * → Every day at 02:00
• */5 * * * * → Every 5 minutes
• 0 0 * * 0 → Every Sunday at midnight

Tip:
Use fixed schedules for system tasks to avoid unnecessary load.

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Command

Defines the command that will be executed.

Notes:

• Commands are executed with system privileges
• Absolute paths are recommended
• If no command is provided and only a script path is defined, the command is created automatically

Example:

bash /boot/optional/scripts/cron/test_script.sh > /dev/null 2>&1

This ensures:

• The script is executed reliably
• No stdout or stderr output is written unless explicitly handled inside the script

Examples:

• /usr/bin/apt update
• /usr/local/bin/backup.sh
• /usr/bin/find /var/log -type f -mtime +7 -delete

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Script

Allows you to select or define a script to be executed instead of a single command.

Use cases:

• Complex logic
• Multi-step operations
• Reusable automation tasks

Notes:

• Scripts must be executable
• Ensure proper shebang (#!/bin/sh, #!/bin/bash, etc.)

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Managing Existing Cron Jobs

All created cron jobs are listed in the overview table.

For each cron job, the following actions are available:

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Start

Enables the cron job.

• The job will run according to its schedule
• Recommended after creation and testing

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Stop

Disables the cron job without deleting it.

Use cases:

• Temporary deactivation
• Troubleshooting
• Maintenance windows

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Edit

Allows you to modify:

• Enabled / Disabled state
• Name
• Schedule
• Command

Note:
Changes take effect immediately after saving.

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Change Script

Updates the script path associated with the cron job.

Important:

• The script itself is not edited here
• Only the filesystem path to the script is changed
• Script content must be modified externally (e.g. via shell, editor, or file manager)

Use cases:

• Switching to a new or updated script version
• Replacing a script without recreating the cron job
• Pointing the job to a different script location

Note: Ensure the target script exists and is executable.

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Delete

Permanently removes the cron job.

Warning:
This action cannot be undone.

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Best Practices

• Test commands and scripts manually before scheduling
• Avoid overly frequent schedules unless required
• Log output for debugging and auditing
• Disable unused cron jobs instead of deleting them

Logging and Output Handling

By default, cron job output can be suppressed or discarded.
Optionally, you can redirect stdout and stderr to a dedicated log file by defining it directly in the Command field.

Benefits:

• Easier debugging
• Better auditing and traceability
• Persistent access to execution results

Example:

bash /boot/optional/scripts/cron/test_script.sh >> /var/log/cron/test_script.log 2>&1

Notes:

• Ensure the log directory exists
• Verify proper file permissions
• Consider log rotation for frequently running jobs

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Summary

Cron Jobs provide a powerful and flexible way to automate system tasks.

Key points:

• Create scheduled tasks using commands or scripts
• Easily start, stop, edit, or delete jobs
• Use clear naming and predictable schedules
• Essential for maintenance, backups, and automation

Proper use of cron jobs ensures a reliable and self-maintaining system.

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