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.
Watch this command run
Command transcript
This sanitized transcript shows the commands and output shape without exposing host details.
$ systemctl list-timers --all --no-pager --plain
NEXT LEFT LAST PASSED UNIT ACTIVATES
Thu 2026-06-25 22:00:00 CDT 7h left Thu 2026-06-25 02:00:00 CDT 12h ago backup.timer backup.service
Fri 2026-06-26 00:05:00 CDT 9h left Thu 2026-06-25 00:05:00 CDT 14h ago certbot.timer certbot.service
Thu 2026-06-25 23:50:00 CDT 8h left Thu 2026-06-25 00:00:10 CDT 14h ago logrotate.timer logrotate.service
n/a n/a Mon 2026-06-22 01:00:00 CDT 3 days ago stale-report.timer stale-report.service
4 timers listed.$ systemctl list-timers --all --no-pager --plain | awk 'NR==1 || /\.timer/ {print $(NF-1), "->", $NF}'
UNIT -> ACTIVATES
backup.timer -> backup.service
certbot.timer -> certbot.service
logrotate.timer -> logrotate.service
stale-report.timer -> stale-report.serviceView commands shown
These are the commands shown in the sanitized transcript.
Commands shown
systemctl list-timers --all --no-pager --plainsystemctl list-timers --all --no-pager --plain | awk 'NR==1 || /\.timer/ {print $(NF-1), "->", $NF}'
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 Upcoming systemd Timers
Cron is not the only scheduler on modern Linux servers.
systemctl list-timers --all --no-pager
Show Failed systemd Units
One command tells you which services systemd already knows are broken.
systemctl --failed --no-pager
Show Context Around the First App Error
The first error often explains more than the last one.
awk '{buf[NR%5]=$0} tolower($0) ~ /(error|exception|fatal)/ {for (i=NR-4;i<=NR;i++) if (i>0) print buf[i%5]; exit}' fixtures/incidents/app.log
Print the Exact systemd Exit Fields
Turn a noisy service failure into four fields you can paste into an incident note.
systemctl show app-worker --property=Result,ExecMainCode,ExecMainStatus,NRestarts --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.
Useful for
- LPIC-1 style command-line practice
- LFCS style performance tasks
- Linux+ style troubleshooting review
Independent study support only. No affiliation, endorsement, exam dumps, or real exam questions.