linux clock 命令介绍和使用案例
clock 命令在 Linux 中并不是一个标准的命令，通常在 Linux 系统中与时间和日期相关的命令主要是 date、hwclock 和 timedatectl
1. date 命令date 命令用于显示和设置系统的日期和时间
使用案例：显示当前日期和时间：输出示例：root@meng:~# dateMon Sep 2 11:00:26 CST 2024设置系统时间（需要 root 权限）：root@meng:~# sudo date -s "2024-09-02 11:01:00"Mon Sep 2 11:01:00 CST 2024root@meng:~# dateMon Sep 2 11:01:02 CST 20242. hwclock 命令hwclock 命令用于访问硬件时钟（RTC），可以用来显示、设置和同步系统时间
root@meng:~# hwclock
2024-09-02 11:01:47.995908+08:00
root@meng:~# which hwclock
/usr/sbin/hwclock
root@meng:~# hwclock --help
Usage:
hwclock [function] [option...]
Time clocks utility.
Functions:
-r, --show display the RTC time
--get display drift corrected RTC time
--set set the RTC according to --date
-s, --hctosys set the system time from the RTC
-w, --systohc set the RTC from the system time
--systz send timescale configurations to the kernel
-a, --adjust adjust the RTC to account for systematic drift
--predict predict the drifted RTC time according to --date
Options:
-u, --utc the RTC timescale is UTC
-l, --localtime the RTC timescale is Local
-f, --rtc <file> use an alternate file to /dev/rtc0
--directisa use the ISA bus instead of /dev/rtc0 access
--date <time> date/time input for --set and --predict
--delay <sec> delay used when set new RTC time
--update-drift update the RTC drift factor
--noadjfile do not use /etc/adjtime
--adjfile <file> use an alternate file to /etc/adjtime
--test dry run; implies --verbose
-v, --verbose display more details
-h, --help display this help
-V, --version display version
For more details see hwclock(8).
3. timedatectl 命令timedatectl 是 systemd 的一部分，用于查询和更改系统时钟及其设置
root@meng:~# timedatectl
Local time: Mon 2024-09-02 11:02:38 CST
Universal time: Mon 2024-09-02 03:02:38 UTC
RTC time: Mon 2024-09-02 03:02:36
Time zone: Asia/Shanghai (CST, +0800)
System clock synchronized: no
NTP service: active
RTC in local TZ: no
root@meng:~# which timedatectl
/usr/bin/timedatectl
root@meng:~# timedatectl --help
timedatectl [OPTIONS...] COMMAND ...
Query or change system time and date settings.
Commands:
status Show current time settings
show Show properties of systemd-timedated
set-time TIME Set system time
set-timezone ZONE Set system time zone
list-timezones Show known time zones
set-local-rtc BOOL Control whether RTC is in local time
set-ntp BOOL Enable or disable network time synchronization
systemd-timesyncd Commands:
timesync-status Show status of systemd-timesyncd
show-timesync Show properties of systemd-timesyncd
Options:
-h --help Show this help message
--version Show package version
--no-pager Do not pipe output into a pager
--no-ask-password Do not prompt for password
-H --host=[USER@]HOST Operate on remote host
-M --machine=CONTAINER Operate on local container
--adjust-system-clock Adjust system clock when changing local RTC mode
--monitor Monitor status of systemd-timesyncd
-p --property=NAME Show only properties by this name
-a --all Show all properties, including empty ones
--value When showing properties, only print the value
See the timedatectl(1) man page for details.
