Cron Doctor

Cron Doctor

Diagnose and triage cron job failures.

Usage

When asked to check cron health or diagnose failures:

1. List All Jobs

# List user's crontab crontab -l # List system crontabs sudo cat /etc/crontab ls -la /etc/cron.d/

2. Check Recent Execution

# Check cron logs (location varies by system) # Debian/Ubuntu: grep CRON /var/log/syslog | tail -50 # RHEL/CentOS: tail -50 /var/log/cron # macOS: log show --predicate 'process == "cron"' --last 1h # Check for specific job output grep "your_job_name" /var/log/syslog | tail -20

3. Identify Problems

Error patterns to watch: "command not found" — Missing executable or PATH issue "Permission denied" — File/directory permissions wrong "No such file or directory" — Script path incorrect "timeout" — Job took too long "ECONNREFUSED" — Network/service down "rate limit" — API throttling Missing output — Job may not be running at all

4. Triage Priority

PriorityCriteria🔴 CriticalTrading, backup, security jobs🟠 HighUser-facing deliveries🟡 MediumMonitoring, research jobs🟢 LowNice-to-have, non-essential

5. Generate Report

• Write to ~/workspace/reports/cron-health-YYYY-MM-DD.md:
• # Cron Health Report - [DATE]
• ## Summary
• ✅ Healthy: X jobs
• ⚠️ Warning: X jobs
• ❌ Failed: X jobs
• ## Failed Jobs
• ### [Job Name]
• **Error:** [message]
• **Last Success:** [date]
• **Priority:** [level]
• **Fix:** [suggested action]
• ## Recommendations
• 1. [Action item]
• 2. [Action item]

6. Common Fixes

ErrorFixCommand not foundUse full path to executable, or set PATH in crontabPermission deniedCheck file permissions, run chmod +x script.shNo outputAdd >> /tmp/job.log 2>&1 to capture outputWrong timezoneSet TZ= in crontab or use system timezoneRate limitReduce frequency or add backoff

7. Debugging Tips

# Test cron environment (cron has minimal PATH) env -i /bin/sh -c 'echo $PATH' # Verify script runs manually /path/to/your/script.sh # Check if cron daemon is running systemctl status cron # Linux launchctl list | grep cron # macOS

Escalation

If 3+ critical jobs failed, alert the user immediately.

Verification Gates

Before claiming diagnosis complete: All failed jobs listed — none skipped or ignored Priority assigned — based on impact, not just recency Fix suggested — actionable next step for each failure Report written — to ~/workspace/reports/cron-health-YYYY-MM-DD.md Critical failures escalated — 3+ critical = alert user