Linux Survival Basics
Read-onlyList Upcoming systemd Timers
Backups, renewals, and cleanup jobs may run as systemd timers, but they are easy to miss if you only inspect cron.
Command
systemctl list-timers --all --no-pagerBefore you run this
System impact: Read-only. Low when scoped to the shown target.
When not to use it: Do not use it to inspect classic cron jobs; check crontabs separately.
Expected output
Timer rows showing NEXT, LEFT, LAST, UNIT, and ACTIVATES.
System impact
Read-only. Nothing changes. systemd prints timer units, next run time, last run time, and the service each timer activates.
Recovery / rollback: no state is changed.
When to use it
Use when checking backups, certificate renewals, cleanup jobs, or unexpected periodic work.
When not to use it
Do not use it to inspect classic cron jobs; check crontabs separately.
next steps
Related commands
List systemd Timers and Last Runs
A timer can be inactive, missed, or waiting for the wrong calendar.
systemctl list-timers --all --no-pager
Map systemd Timers to Services
A timer is only half the scheduled job. The service is the payload.
systemctl list-timers --all --no-pager --plain | awk 'NR==1 || /\.timer/ {print $(NF-1), "->", $NF}'
Check apt Daily Timers
Automatic apt timers can explain locks that seem mysterious.
systemctl list-timers apt-daily* --no-pager
Show Failed systemd Units
One command tells you which services systemd already knows are broken.
systemctl --failed --no-pager
Spot Stale systemd Timers
The suspicious timer is the one with no next run.
systemctl list-timers --all --no-pager --plain | awk 'NR==1 || $1=="n/a" || /backup\.timer|logrotate\.timer/'
Study mapping
Use this as independent command practice: read the notes, predict the output, then compare it with the example before using a real shell.
Independent study support only. No affiliation, endorsement, exam dumps, or real exam questions.