Linux Survival Basics
Read-onlyMap systemd Timers to Services
systemctl list-timers shows timer units, but you need to see what service each timer activates.
Command
systemctl list-timers --all --no-pager --plain | awk 'NR==1 || /\.timer/ {print $(NF-1), "->", $NF}'Before 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 the service definition itself; follow up with systemctl cat on the unit.
Expected output
Mappings such as backup.timer -> backup.service.
System impact
Read-only. Nothing changes. The command condenses timer rows into timer-to-service mappings.
Recovery / rollback: no state is changed.
When to use it
Use when auditing scheduled work on modern Linux systems that may not rely only on cron.
When not to use it
Do not use it to inspect the service definition itself; follow up with systemctl cat on the unit.
next steps
Related commands
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/'
List systemd Timers and Last Runs
A timer can be inactive, missed, or waiting for the wrong calendar.
systemctl list-timers --all --no-pager
List Upcoming systemd Timers
Cron is not the only scheduler on modern Linux servers.
systemctl list-timers --all --no-pager
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
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.