Wednesday, December 9, 2009

Linux change date and hardware clock

SkyHi @ Wednesday, December 09, 2009
[root@home ~]# date 010817092010
Fri Jan 8 17:09:00 PST 2010

[root@home ~]# date
Fri Jan 8 17:09:02 PST 2010

[root@mustang ~]# hwclock --help
hwclock - query and set the hardware clock (RTC)

Usage: hwclock [function] [options...]

--help show this help
--show read hardware clock and print result
--set set the rtc to the time given with --date
--hctosys set the system time from the hardware clock
--systohc set the hardware clock to the current system time
--adjust adjust the rtc to account for systematic drift since
the clock was last set or adjusted
--getepoch print out the kernel's hardware clock epoch value
--setepoch set the kernel's hardware clock epoch value to the
value given with --epoch
--version print out the version of hwclock to stdout

--utc the hardware clock is kept in coordinated universal time
--localtime the hardware clock is kept in local time
--directisa access the ISA bus directly instead of /dev/rtc
--badyear ignore rtc's year because the bios is broken
--date specifies the time to which to set the hardware clock
--epoch=year specifies the year which is the beginning of the
hardware clock's epoch value
--noadjfile do not access /etc/adjtime. Requires the use of
either --utc or --localtime

[root@home ~]# hwclock --show
Wed 09 Dec 2009 05:13:18 PM PST -0.887453 seconds

//sync hardwareclock
[root@home ~]# hwclock -w