Linux练习命令一

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limeng23 2015-08-29 13:58:37 ©著作权

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1.clock 和hwclock的用法

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

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

Functions:
-h | --help         show this help
-r | --show         read hardware clock and print result
       --set          set the rtc to the time given with --date
-s | --hctosys      set the system time from the hardware clock
-w | --systohc      set the hardware clock to the current system time
       --systz        set the system time based on the current timezone
       --adjust       adjust the rtc to account for systematic drift since
                      the clock was last set or adjusted
-c | --compare      periodically compare the system clock with the CMOS clock
       --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
-v | --version      print out the version of hwclock to stdout

Options:
-u | --utc          the hardware clock is kept in UTC
       --localtime    the hardware clock is kept in local time
-f | --rtc=path     special /dev/... file to use instead of default
       --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
       --adjfile=path specifies the path to the adjust file (default is
                      /etc/adjtime)
       --test         do everything except actually updating the hardware
                      clock or anything else
-D | --debug        debug mode

hwclock –s 同步硬件时间到系统时间

hwclock –w 同步系统时间到硬件时间

hwclock –r 显示当前硬件时间状态

2.cd 进入指定目录

cd / 直接跳转到根目录

cd etc 或cd /etc进入根目录下的etc目录前一个是相对路径，后一个是绝对路径

cd .. 返回上一级目录

3cal 调出日历

CAL(1)

NAME
cal - display a calendar

SYNOPSIS
cal [options] [[[day] month] year]

cal 显示当前日历

cal year 显示所属年份日历

cal -s 本月日历按Sunday列出

cal –m 本月日历按Monday列出

4. pwd 显示当前工作目录命令行下直接pwd

5. ls

NAME
ls - list directory contents

SYNOPSIS
ls [OPTION]... [FILE]...

ls：list
列出指定路径下的文件或目录的属性信息

Metadata：属性数据
data：数据

        ls [OPTION]... [FILE]...
            -l: 使用长格式显示
                drwxr-xr-x 1 root root    8 Aug 23 08:47 .cache
                    d: 文件类型
                    rwxr-xr-x：权限，mode
                    1：文件被硬链接的次数
                    root: owner，属主；
                    root: group, 属组
                    8：size，默认为字节
                    Aug 23 08:47 修改时间戳
                    .cache：文件名
            -d：显示目录自身属性
            -h: human-readable
            -a：显示所有文件，包括.开头的隐藏文件
                .: 当前目录
                ..: 父目录
            -r: reverse，逆序显示
            -R: recusive，递归