Cron Expression: Every Day at 1:00 AM (0 1 * * *)
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Cron Expression: Every Day at 1:00 AM (0 1 * * *)
The cron expression 0 1 * * * executes a task every day at 1:00 AM, making it ideal for post-midnight operations, backups, and maintenance tasks that should run after initial daily jobs complete.
Expression Breakdown
0 1 * * *
│ │ │ │ │
│ │ │ │ └─── Day of week: * (every day)
│ │ │ └───── Month: * (every month)
│ │ └─────── Day of month: * (every day)
│ └───────── Hour: 1 (at hour 1, 1:00 AM)
└─────────── Minute: 0 (at minute 0)
Field Values
| Field | Value | Meaning |
|---|---|---|
| Minute | 0 | At minute 0 |
| Hour | 1 | At hour 1 (1:00 AM) |
| Day of Month | * | Every day (1-31) |
| Month | * | Every month (1-12) |
| Day of Week | * | Every day of week (0-7) |
Execution Time
This expression runs once per day at:
- 01:00 (1:00 AM)
Common Use Cases
1. Secondary Backups
0 1 * * * /usr/local/bin/secondary-backup.sh
Create secondary backups after midnight backups complete.
2. Data Processing
0 1 * * * /usr/bin/python3 /scripts/process-data.py
Process data that depends on midnight jobs completing first.
3. Cleanup Operations
0 1 * * * /usr/local/bin/cleanup-temp-files.sh
Clean up temporary files, old cache entries, or stale data.
4. Database Maintenance
0 1 * * * /usr/local/bin/db-vacuum.sh
Run database vacuum, optimization, or maintenance tasks.
Example Implementations
Secondary Backup Script
#!/bin/bash
# /usr/local/bin/secondary-backup.sh
BACKUP_DIR="/var/backups/secondary"
SOURCE_DIR="/var/data"
TIMESTAMP=$(date +%Y%m%d)
LOG_FILE="/var/log/backups.log"
mkdir -p $BACKUP_DIR
# Create secondary backup
rsync -av --delete \
/var/backups/primary/ \
$BACKUP_DIR/backup_$TIMESTAMP/ >> $LOG_FILE 2>&1
# Clean up backups older than 14 days
find $BACKUP_DIR -type d -mtime +14 -exec rm -rf {} \;
echo "$(date): Secondary backup completed" >> $LOG_FILE
Python Data Processing
# process-data.py
from datetime import datetime, timedelta
import sqlite3
def process_data():
conn = sqlite3.connect('/var/data/app.db')
cursor = conn.cursor()
# Process data from previous day
yesterday = datetime.now() - timedelta(days=1)
# Aggregate and process
cursor.execute('''
INSERT INTO daily_aggregates (date, total, processed_at)
SELECT DATE(timestamp), COUNT(*), ?
FROM raw_data
WHERE DATE(timestamp) = DATE(?)
GROUP BY DATE(timestamp)
''', (datetime.now(), yesterday))
conn.commit()
conn.close()
print(f"{datetime.now()}: Data processing completed")
if __name__ == '__main__':
process_data()
Best Practices
- Dependency Management: Ensure midnight jobs complete before 1 AM jobs start
- Error Handling: Implement comprehensive error handling and logging
- Locking: Use file locks to prevent concurrent execution
- Monitoring: Set up alerts for failed jobs
- Resource Management: Monitor system resources during execution
When to Use
✅ Good for:
- Secondary backups
- Post-midnight data processing
- Cleanup operations
- Database maintenance
- Tasks dependent on midnight jobs
❌ Avoid for:
- Real-time critical operations
- Tasks requiring immediate execution
Related Patterns
| Pattern | Expression | Description |
|---|---|---|
| Daily at midnight | 0 0 * * * | Start of day |
| Daily at 1 AM | 0 1 * * * | One hour after midnight |
| Daily at 2 AM | 0 2 * * * | Two hours after midnight |
| Daily at 6 AM | 0 6 * * * | Early morning |
Conclusion
The 0 1 * * * expression is perfect for tasks that need to run after midnight jobs complete. It's commonly used for secondary backups, data processing, and cleanup operations that should execute during low-traffic early morning hours.
Need to generate a cron expression?
Use CronOS to generate any cron expression you wish with natural language. Simply describe what you need, and we'll create the perfect cron expression for you. It's completely free!