What is Cron and Crontab?
Cron is a daemon that runs scheduled commands. Crontab is the configuration file.
Each line in crontab has the format:
* * * * * command
│ │ │ │ └── day of the week (0-7, 0 and 7 = Sunday)
│ │ │ └──── month (1-12)
│ │ └────── day of the month (1-31)
│ └──────── hour (0-23)
└────────── minute (0-59)
Practical Examples for SEO
Daily Indexing via IndexFast
If you use the IndexFast PHP script to send URLs via Google Indexing API:
# Run daily at 6:00 AM
0 6 * * * php /var/www/html/google_indexing.php >> /var/log/indexing.log 2>&1
💡 >> and 2>&1
The >> symbol appends the output to the log file. 2>&1 redirects errors there as well.
Updating Sitemap
# Update sitemap every 6 hours
0 */6 * * * php /var/www/html/generate_sitemap.php
Weekly SEO Audit
# Every Sunday at 3:00 — check broken links
0 3 * * 0 python3 /scripts/check_links.py >> /var/log/links_audit.log
Pinging Google after an update
# Ping Google every 30 mins about sitemap update
*/30 * * * * curl -s "https://www.google.com/ping?sitemap=https://yoursite.com/sitemap.xml" > /dev/null
How to Configure Crontab
- Connect to the server via SSH
- Open the crontab editor:
crontab -e - Add lines with tasks (format described above)
- Save the file (in nano: Ctrl+O, Enter, Ctrl+X)
- Check that the task is added:
crontab -l
If you have no SSH access
Most hosting panels have a graphical interface for cron jobs.
⚠️ Important: Absolute Paths
Always specify absolute paths to executable files in cron.
Cron for Automatic Indexing with IndexFast
The IndexFast PHP script is perfect for cron. It:
- Reads URLs from sitemap.xml
- Sends them via Google Indexing API
- Logs the results of each request
- Stops when the daily quota (200 URLs) is reached
Want to do this without cron and SSH?
IndexFast PRO has a built-in scheduler — configure it directly in the dashboard.
🚀 Try for free →Monitoring Cron Jobs
By default, cron sends output to root email. To get emails, add:
MAILTO="[email protected]"
Or view the system log: grep CRON /var/log/syslog