Cron Is Lying to You

Your crontab fired. The process exited 0. The business artifact still was not there.

*Cron Is Lying to You* is a field manual for operators who need schedules they can trust. Jules Hart opens on real situations—empty exports, overlapping cleanups, DST arguments, catch-up storms—then walks concrete fixes before reference material. You will learn to separate scheduler fire from process success from business success; to tame PATH, cwd, and env under cron; to prove runs with logs, mail realism, and sentinel files; to design idempotent jobs; to handle timezones and DST without folklore; to stop overlaps with flock; and to choose when plain cron is enough versus when systemd timers win with OnCalendar, Persistent=, and RandomizedDelaySec=.

A worked lab migrates one real job from crontab to a oneshot + timer pair. Observability chapters replace "grep the mail folder" with status, journalctl, and freshness probes. Pocket drills and a short reference close the book.

Written for Linux sysadmins and on-call engineers. Standalone title from Jules Hart Books—no series branding. Approximate length: trade ebook, ~25k words.