Write the correctly adjusted system clock value to the hardware clock.
Which command is appropriate?
hwclock --systohc means system clock to hardware clock and updates the RTC.
Detailed explanation
hwclock --showIncorrect. --show only reads the RTC.
Incorrect. --show only reads the RTC.
hwclock --hctosysIncorrect. --hctosys copies RTC to system clock.
Incorrect. --hctosys copies RTC to system clock.
hwclock --systohcCorrect. It writes the system clock to the RTC.
Correct. It writes the system clock to the RTC.
date --hwclockIncorrect. date has no --hwclock synchronization option.
Incorrect. date has no --hwclock synchronization option.
Try it yourself
An example you can run in a temporary verification environment.
hwclock --help | grep -E -- '--systohc|--hctosys'Expected result
両方向の同期オプション説明Key points
- systohc means system to hardware
- hctosys is the reverse
- Writing needs permission
Notes
- Environment: util-linux hwclock help / 時計変更なし
- 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.