The clock that is managed by Linux kernel is not the same as the hardware clock. Hardware clock runs even when you shutdown your system. Hardware clock is also called as BIOS clock. You can change the date and time of the hardware clock from the BIOS. However, when the system is up and running, you can still view and set the hardware date and time using Linux hwclock command as explained in this tutorial.
Just type hwclock, which will display the date and time of your system’s hardware clock. This is the same date and time that you’ll see from the BIOS screen. You can also use option -r, or –show to display the date and time.
# hwclock