How to debug cron jobs: logging, email output, and troubleshooting silent failures

How this is calculated

Three debugging strategies work. First, redirect STDOUT and STDERR to a log file: 0 * * * * /path/to/script >> /var/log/myjob.log 2>&1. Second, set MAILTO=you@example.com at the top of your crontab to get email on every execution. Third, wrap the command in a script that logs the start time, exit code, and runtime duration. The most common silent failure cause is missing environment: cron runs with a minimal PATH (typically /usr/bin:/bin) and no shell profile loaded. Always use absolute paths to executables in cron commands, or set PATH explicitly in the crontab.

Verdict

Never deploy a cron job without output capture. At minimum, redirect to a log file. For production, add structured logging with timestamps, exit codes, and runtime. And always use absolute paths or set PATH in the crontab.