Cron & Task Scheduling (Cron/Systemd Timers/At)

Stop at jobs from disappearing into the void when you reboot

🧩 The Challenge

Dealing with a one-off task using the at command is great until the power flickers and your job just evaporates. I once lost three hours of log processing work because I assumed the system would pick it back up after a reboot.

💡 The Fix

You need to make sure the atd service is actually enabled to persist across restarts. It’s one of those things that’s rarely set to start by default on minimal installs.

systemctl enable --now atd

⚙️ Why It Works

Setting this service to start on boot ensures that the queue file in /var/spool/cron/atjobs gets re-read when the kernel comes back up. Without the daemon running, your jobs just sit in the filesystem waiting for a process that never launches.

🚀 Pro-Tip: Use atq to check if your job is actually queued before you walk away for the weekend.

Linux Tips & Tricks | © ngelinux.com | 8/9/2026