Start backup.timer now and make it start automatically on future boots.
Which command is appropriate?
systemctl enable --now UNIT both enables a unit for boot and starts it immediately.
Detailed explanation
systemctl start backup.serviceIncorrect. It starts a service once and does not enable the timer.
Incorrect. It starts a service once and does not enable the timer.
systemctl enable backup.timerIncorrect. It enables the timer for boot but does not start it now.
Incorrect. It enables the timer for boot but does not start it now.
systemctl enable --now backup.timerCorrect. It enables and starts backup.timer.
Correct. It enables and starts backup.timer.
systemctl daemon-reload backup.timerIncorrect. daemon-reload reloads definitions but does not enable or start a unit.
Incorrect. daemon-reload reloads definitions but does not enable or start a unit.
Try it yourself
An example you can run in a temporary verification environment.
printf '%s\n' 'enable: persistent boot activation' 'now: start immediately'Expected result
enable: persistent boot activation
now: start immediatelyKey points
- enable for boot
- --now starts now
- Target the .timer
Notes
- Environment: 状態変更しない意味確認
- Command output formatting can vary slightly by distribution or tool version.
- Run the example in a temporary directory or process when possible.
Foundation review
Read the scope first
Check whether the command acts on the current shell, a new process, an existing process, or a file.
Verify the observable result
Use the supplied command and compare the output with the expected result.