Automating tasks on a Linux server helps save time and ensures consistency. An effective way to achieve this is by creating a shell script (.sh) and scheduling it with crontab. In this article, we will guide you through creating a backup script and setting it up to run automatically on a Linux server.
What You’ll Learn
- How to write a shell script for data backups.
- How to schedule it using crontab.
- Best practices for managing backups on Linux.
Step 1: Writing the Shell Script
Below is an example of a shell script that performs database and file backups:
#!/bin/bash
# Create backup directory
backup_dir="/home/backup/$(date +'%Y-%m')"
mkdir -p $backup_dir
# Backup database
cd /home/source && ./vendor/bin/drush sql-dump > "$backup_dir/db_$(date +'%Y-%m-%dT%H-%M').sql.gz" --gzip
cd /home/source && ./vendor/bin/drush sql-dump > "$backup_dir/db_shared_$(date +'%Y-%m-%dT%H-%M').sql.gz" --gzip
# Backup files directory
rsync -av --backup --suffix=.bak /home/source/web/sites/default/files/ /home/backup/files
# Delete backups older than 10 days
find /home/backup/* -type d -mtime +10 -exec rm -r {} \;Explanation:
- #!/bin/bash: Declares this as a Bash script.
- mkdir -p: Creates a directory based on the year and month if it doesn’t exist.
- drush sql-dump: Exports the database and compresses it with gzip.
- rsync: Synchronizes files to the backup directory with a .bak suffix for overwritten files.
- find: Deletes backups older than 10 days.
Save this script as backup.sh and make it executable:
chmod +x backup.shStep 2: Scheduling with Crontab
To automate the script, use crontab. Open the crontab file:
crontab -e0 2 * * * /home/backup.shCrontab Syntax:
- 0 2 * * *: Runs at 2:00 AM every day (minute, hour, day of month, month, day of week).
- /home/backup.sh: Path to the script.
Save and exit. Verify the schedule with:
crontab -lStep 3: Testing the Script
Run the script manually to ensure it works:
./backup.shCheck the backup directory (/home/backup) to see the generated files.
Best Practices
- Log Output: Redirect script output to a log file (>> /var/log/backup.log 2>&1).
- Permissions: Ensure the script has appropriate execution rights.
- Storage: Monitor disk space to avoid filling up the server.
Conclusion
By following these steps, you can automate backups on a Linux server using a shell script and crontab. This method is efficient, reliable, and widely used by system administrators.
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