The hwclock command in Linux is used to access and modify the hardware clock. The hardware clock is a battery-backed clock that keeps track of the system time even when the machine is powered off.
The hwclock command takes the following arguments:
options: Optional arguments that control the behavior ofhwclock.
The following are some of the most common options for the hwclock command:
-r: Reads the hardware clock.-w: Writes the hardware clock.-s: Sets the hardware clock to the system time.-d: Displays the drift between the hardware clock and the system time.-f: Specifies the file to read or write the hardware clock from or to.
For example, the following command will read the hardware clock:
hwclock -r
The hwclock command is a useful tool for setting and adjusting the hardware clock. It is a valuable tool for anyone who needs to keep their system time accurate.
Here are some additional things to keep in mind about hwclock:
- The
hwclockcommand must be run as root or by a user who has permission to modify the hardware clock. - The
hwclockcommand can be used to set the hardware clock to UTC or to local time. - The
hwclockcommand can be used to adjust the hardware clock for drift.
Here are some examples of how to use hwclock:
- To read the hardware clock:
hwclock -r
- To write the hardware clock:
hwclock -w
- To set the hardware clock to UTC:
hwclock -s -f /etc/adjtime
- To set the hardware clock to local time:
hwclock -s -f /etc/localtime
- To adjust the hardware clock for drift:
hwclock -s -f /etc/adjtime -d
The hwclock command is a powerful and versatile tool that can be used to access and modify the hardware clock. It is a valuable tool for anyone who needs to keep their system time accurate.