nerdexam
Linux_Foundation

LFCS · Question #523

On a dual boot system, every time the system is booted back into Linux the time has been set backward by one day. Which of the following commands will correct the problem?

The correct answer is B. hwclock --systohc --localtime. When a dual-boot system shows time discrepancies in Linux after booting into another OS, it usually indicates a conflict in how the operating systems interpret the hardware clock (RTC).

Submitted by rania.sa· Apr 18, 2026Operation of Running Systems

Question

On a dual boot system, every time the system is booted back into Linux the time has been set backward by one day. Which of the following commands will correct the problem?

Options

  • Adate -d '+ 1 day'
  • Bhwclock --systohc --localtime
  • Cntpdate pool.ntp.org
  • Dtime hwclock

How the community answered

(46 responses)
  • A
    2% (1)
  • B
    83% (38)
  • C
    11% (5)
  • D
    4% (2)

Why each option

When a dual-boot system shows time discrepancies in Linux after booting into another OS, it usually indicates a conflict in how the operating systems interpret the hardware clock (RTC).

Adate -d '+ 1 day'

The `date -d '+ 1 day'` command would simply advance the system date by one day, which is a temporary fix and does not address the underlying issue of how Linux interprets the hardware clock.

Bhwclock --systohc --localtimeCorrect

The `hwclock --systohc --localtime` command configures the system to interpret the hardware clock (RTC) as local time and then saves the current system time to the RTC using this interpretation. This resolves issues where Windows sets the RTC to local time and Linux incorrectly interprets it as UTC, causing the apparent time shift.

Cntpdate pool.ntp.org

The `ntpdate pool.ntp.org` command synchronizes the system time with an NTP server, but it does not reconfigure how Linux interacts with the hardware clock, so the problem would likely reoccur on reboot.

Dtime hwclock

The command `time hwclock` would measure the execution time of the `hwclock` command, not configure the hardware clock settings to resolve time discrepancies.

Concept tested: Hardware clock synchronization in dual-boot systems

Source: https://man7.org/linux/man-pages/man8/hwclock.8.html

Topics

#Hardware Clock#System Time#Time Synchronization#hwclock

Community Discussion

No community discussion yet for this question.

Full LFCS Practice