linux系统引导流程

linux 查看软件时间 date

[root@localhost test]# date

Sun Jan 15 19:20:01 PST 2012

[root@localhost test]#

hwclock 软件时钟

[root@localhost test]# hwclock --help

hwclock - query and set the hardware clock (RTC)

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

Functions:

--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 依据硬件时钟设置软件时钟 --systohc set the hardware clock to the current system time 依据软件时钟设置硬件时钟

--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

Options:

--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@localhost test]#

Eg.

[root@localhost test]# date

Sun Jan 15 19:26:05 PST 2012

[root@localhost test]# hwclock

Sun 15 Jan 2012 07:26:10 PM PST -0.128598 seconds

[root@localhost test]# hwclock --hctosys

[root@localhost test]# date