Quickly inspect active and scheduled systemd timers from the command line and act on them. 16.11.2025 | reading time: 3 min Timers in systemd schedule services for future execution; learn how to see which timers are active, when they will run next and how to inspect a specific timer from the shell. A hands-on check Try this on a Linux host: list timers and inspect one: ```systemctl list-timers --all --no-pager NEXT LEFT LAST PASSED UNIT ACTIVATES Fri 2025-11-21 02:00:00 CET 12h Thu 2025-11-20 02:00:00 CET 1d ago fstrim.timer fstrim.service Sat 2025-11-22 00:00:00 CET 1 day Thu 2025-11-20 00:00:00 CET 1d ago logrotate.timer logrotate.service``` then inspect a single timer for details: ```systemctl status fstrim.timer ● fstrim.timer - Discard unused blocks once a week Loaded: loaded (/lib/systemd/system/fstrim.timer; enabled) Active: active (waiting) since Thu 2025-11-20 02:00:00 CET; 1d 3h ago Next elapse: Fri 2025-11-21 02:00:00 CET (in 12h)``` and for a machine-readable timestamp use: ```systemctl show -p NextElapseUSec fstrim.timer NextElapseUSec=173???.???```. Act and adapt Enable or start a timer with `systemctl enable --now name.timer` to make it persistent and running, stop or disable it with `systemctl stop`/`disable`, create transient timers with `systemd-run --on-calendar` for one-off schedules and parse calendar expressions with `systemd-analyze calendar 'Mon *-*-* 02:00:00'` to verify the next matching date; use `journalctl -u name.service` or `journalctl -u name.timer` to trace past triggers and failures. When systemd timers shine Use timers instead of cron when you want tight integration with units, dependencies and logging, schedule jobs relative to boot or idle, or require deterministic ordering with other systemd units; inspect properties such as NextElapseUSec, LastTriggerUSec and accuracy with `systemctl show` for scripting and automation. Other relevant timing tools Classic alternatives include cron for simple recurring jobs, anacron for machines that sleep, and at for one-shot scheduling; each has trade-offs versus systemd timers depending on persistence, ordering and dependency needs. Wrap-up and next steps You now know how to list timers, inspect details and act on them; practice on a lab VM by enabling, triggering and reading logs, then explore `systemd-analyze` and `systemctl show` for automation hooks — and if you want to deepen Linux skills, consider certification like CompTIA Linux+ or LPIC-1 and intensive exam preparation at bitsandbytes.academy. Join Bits & Bytes Academy First class LINUX exam preparation. processes boot-process utilities scripting troubleshooting
