Writing the system clock to the RTC | LinuC Level 1 102 Exam original practice question

1.09.1Basic

Write the correctly adjusted system clock value to the hardware clock.

Which command is appropriate?

Hint 1: Focus on clock layers

Separate the system clock, RTC, timezone rules, and NTP synchronization before comparing the commands or settings.

Hint 2: Key terms

Review the short definitions of system clocks, RTC, timezones, and NTP synchronization involved.

System clock: The running clock used by the kernel and ordinary time-aware commands.
RTC: A hardware real-time clock that can provide an initial value during boot.
--systohc: The hwclock direction that copies system time to the RTC.
--hctosys: The hwclock direction that copies RTC time to the system clock.
--show: The hwclock option that displays the RTC without changing either clock.

Detailed explanation

Incorrecthwclock --show

Incorrect. --show only reads the RTC.

Incorrecthwclock --hctosys

Incorrect. --hctosys copies RTC to system clock.

Correcthwclock --systohc

Correct. It writes the system clock to the RTC.

Incorrectdate --hwclock

Incorrect. date has no --hwclock synchronization option.

An example you can run in a temporary verification environment.

hwclock --help | grep -E -- '--systohc|--hctosys'

両方向の同期オプション説明

Foundation review

The kernel-maintained time used by applications and timestamps.

The battery-backed hardware clock used to seed time during boot.

A process that compares a clock with remote time sources and corrects drift.

Question IDKL-102-1071

Environmentutil-linux hwclock help / 時計変更なし

Last technical review2026-08-13

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