Linux in a Nutshell, Third Edition

Name

hwclock

Synopsis

hwclock [options]

Description

System administration command. Read or set the hardware clock. This command maintains change information in /etc/adjtime, which can be used to adjust the clock based on how much it drifts over time. hwclock replaces the clock command. The single-letter options are included for compatibility with the older command.

Options

You may specify only one of the following options:

-a

Adjust the hardware clock based on information in /etc/adjtime and set the system clock to the new time.

--adjust

Adjust the hardware clock based on information in /etc/adjtime.

--date date

Meaningful only with the --set option. date is a string appropriate for use with the date command.

--debug

Print information about what hwclock is doing.

-r, --show

Print the current time stored in the hardware clock.

-s, --hctosys

Set the system time in accordance with the hardware clock.

--set

Set the hardware clock according to the time given in the --date parameter.

--test

Do not actually change anything. This is good for checking syntax.

-u, --utc

The hardware clock is stored in Universal Coordinated Time.

--version

Print version and exit.

-w, --systohc

Set the hardware clock in accordance with the system time.