LFCS Operation of Running Systems Practice Question
A Linux server is configured with a custom systemd service unit for a backup script. After editing /etc/systemd/system/backup.service to add an EnvironmentFile directive, the administrator runs 'systemctl start backup' but systemctl status shows the unit still using the old environment. Which command should the administrator run to apply the unit file changes?
⚠ Common exam trap
The trap here is assuming that restarting a service after editing its unit file is enough to apply the changes, when systemd must first reload its configuration.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
systemctl daemon-reload
After editing a systemd unit file, systemd continues using the previously loaded definition until it is told to reload. The daemon-reload subcommand makes systemd re-parse all unit files, applying changes such as new EnvironmentFile directives. Only then will a subsequent start or restart use the updated environment. The other subcommands act on the running service or enablement state without refreshing the unit definition.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
systemctl reenable backup
Why it's wrong here
systemctl reenable re-creates the symbolic links that control whether the unit starts at boot. It does not refresh the in-memory unit definition. The EnvironmentFile directive is part of the service definition, not the enablement state, so reenabling does not cause systemd to parse the updated file.
- ✓
systemctl daemon-reload
Why this is correct
systemd reads unit files into memory when it starts or when a unit is first loaded. After modifying a unit file, systemd must reload its configuration to pick up changes. Without daemon-reload, systemctl start uses the cached unit definition and ignores the new EnvironmentFile, so the service continues with the old environment.
- ✗
systemctl restart backup
Why it's wrong here
systemctl restart stops and starts the unit, but it does not cause systemd to re-read the modified unit file. The old unit definition remains in memory, so the EnvironmentFile addition is not applied. A restart alone is insufficient after editing a unit file; daemon-reload must be run first.
- ✗
systemctl reload backup
Why it's wrong here
systemctl reload asks the running service to reload its own configuration, typically via a signal like SIGHUP. It does not make systemd re-read the unit file. Since the unit file itself was changed, reloading the service process has no effect on the environment variables systemd passes when starting the service.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Linux Foundation exam blueprint
This LFCS practice question is part of Courseiva's free Linux Foundation certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the LFCS exam.