Cron jobs for scheduled tasks in Raspberry Pi

Introduction

Cron jobs help you run commands or scripts automatically at set times. This saves you from doing repetitive tasks manually.

You want to turn on a light every day at 7 PM.

You need to back up files every night without forgetting.

You want to check your system status every hour.

You want to run a script to update weather info every morning.

You want to clean temporary files every week automatically.

Syntax

Raspberry Pi

minute hour day_of_month month day_of_week command_to_run

Each part is a number or symbol that tells when to run the command.

Use * to mean 'every' for that time part.

Examples

Runs the script at 7:00 AM every day.

Raspberry Pi

0 7 * * * /home/pi/turn_on_light.sh

Runs backup script at 10:30 PM every Monday.

Raspberry Pi

30 22 * * 1 /home/pi/backup.sh

Runs the status check every 15 minutes.

Raspberry Pi

*/15 * * * * /home/pi/check_status.sh

Sample Program

This example shows how to edit the cron table to schedule a script. You open the cron editor, add a line with the time and command, then save it.

Raspberry Pi

# Open terminal on Raspberry Pi
crontab -e

# Add this line to run a script every day at 8 AM
0 8 * * * /home/pi/myscript.sh

# Save and exit the editor

# The script /home/pi/myscript.sh will run automatically at 8 AM daily

Important Notes

Make sure your script has execute permission: chmod +x /home/pi/myscript.sh

Use full paths in your scripts because cron runs with limited environment.

Check cron logs if your job does not run: grep CRON /var/log/syslog

Summary

Cron jobs automate tasks by running commands at scheduled times.

Use the crontab editor to add or change cron jobs.

Always test your scripts manually before scheduling them.