Cron

This is a comprehensive cron reference that covers everything from basic crontab syntax to production-ready job management. You get clear examples of time expressions, special characters, and file locations across different distros. What makes it useful is the practical stuff: a battle-tested script template with locking to prevent duplicate runs, proper logging patterns, and environment variable handling that actually works in cron's stripped-down context. The troubleshooting section addresses the usual pain points like missing PATH variables and permission issues. If you're setting up scheduled tasks beyond trivial one-liners, the examples for database backups, log rotation, and flock-based single instance execution will save you time.