Linux Survival Basics
Read-onlyRead the Failure Cause in systemctl Status
A systemd service is failed and you need the active state, exit status, unit paths, and the most recent failure lines in one read-only check.
Command
systemctl status app-worker --no-pager --lines=50Before you run this
System impact: Read-only. Low when scoped to the shown target.
When not to use it: Do not stop at status when the failure is intermittent, old, or missing context; follow up with journalctl and systemctl show.
Expected output
A failed active state, Result value, ExecStart exit status, and recent lines showing the failing startup step.
System impact
Read-only. Nothing changes. systemctl prints service metadata, process exit status, and recent journal lines.
Recovery / rollback: no state is changed.
When to use it
Use first when a specific service is failed and you need a fast summary before deeper journal or unit-file inspection.
When not to use it
Do not stop at status when the failure is intermittent, old, or missing context; follow up with journalctl and systemctl show.
Watch this command run
Command transcript
This sanitized transcript shows the commands and output shape without exposing host details.
$ systemctl --failed --no-pager
UNIT LOAD ACTIVE SUB DESCRIPTION
app-worker.service loaded failed failed Background job worker
api.service loaded failed failed Example API service
2 loaded units listed.$ systemctl status app-worker --no-pager --lines=50
● app-worker.service - Background job worker
Loaded: loaded (/etc/systemd/system/app-worker.service; enabled; preset: enabled)
Drop-In: /etc/systemd/system/app-worker.service.d
└─override.conf
Active: failed (Result: exit-code) since Thu 2026-06-25 14:22:17 CDT; 4min ago
Duration: 1.243s
Process: 2144 ExecStart=/srv/app/bin/worker --queue default (code=exited, status=217/USER)
Main PID: 2144 (code=exited, status=217/USER)
CPU: 38ms
Jun 25 14:22:17 vps systemd[1]: Started app-worker.service - Background job worker.
Jun 25 14:22:17 vps systemd[2144]: app-worker.service: Failed to determine user credentials: No such process
Jun 25 14:22:17 vps systemd[2144]: app-worker.service: Failed at step USER spawning /srv/app/bin/worker: No such process
Jun 25 14:22:17 vps systemd[1]: app-worker.service: Main process exited, code=exited, status=217/USER
Jun 25 14:22:17 vps systemd[1]: app-worker.service: Failed with result 'exit-code'.View commands shown
These are the commands shown in the sanitized transcript.
Commands shown
systemctl --failed --no-pagersystemctl status app-worker --no-pager --lines=50
next steps
Related commands
Compare Failure Output With the Effective Unit
Put the failed step next to the unit config that created it.
systemctl status app-worker --no-pager --lines=50 && systemctl cat app-worker
Inspect One Service Without Pager Traps
Make systemctl status safe for scripts, screenshots, and quick incident notes.
systemctl status nginx --no-pager --lines=30
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
Show Failed systemd Units
One command tells you which services systemd already knows are broken.
systemctl --failed --no-pager
Reset Failed State After Capturing Evidence
Clear the red failed state only after you have captured the evidence.
systemctl reset-failed app-worker
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.