[root@linux ~]# startx

Fedora Core release 3 (Heidelberg)
Kernel 2.6.11-1.27_FC3 on an i686

linux login: root
Password:
[root@linux ~]# _

[root@linux ~]# exit

[root@linux ~]# command [-options] parameter1 parameter2 ...
                  指令     选项      参数(1)    参数(2)
说明：
0. 一行指令中第一个输入的绝对是『指令(command)』或『可执行文件案』
1. command 为指令的名称，例如变换路径的指令为 cd 等等；
2. 中刮号[]并不存在于实际的指令中，而加入参数设定时，通常为 - 号，例如 -h；
   有时候完整参数名称会输入 -- 符号，例如 --help；
3. parameter1 parameter2.. 为依附在 option 后面的参数，
   或者是 command 的参数； 
4. command, -options, parameter1.. 这几个咚咚中间以空格来区分，
   不论空几格 shell 都视为一格； 
5. 按下 [Enter] 按键后，该指令就立即执行。[Enter] 按键为 <CR> 字符，
   他代表着一行指令的开始启动。
6. 指令太长的时候，可以使用 \ 符号来跳脱 [Enter] 符号，
   使指令连续到下一行。注意！ \ 后就立刻接特殊字符。
其他：
a. 在 Linux 系统中，英文大小写字母是不一样的。举例来说， cd 与 CD 并不同。
b. 更多的介绍等到 bash 时，再来详述。

[root@linux ~]# ls -al /root
[root@linux ~]# ls           -al   /root

[root@linux ~]# date
[root@linux ~]# Date
[root@linux ~]# DATE

[root@linux ~]# LANG=en
[root@linux ~]# LANGUAGE=en
[root@linux ~]# LC_ALL=en
[root@linux ~]# LC_CTYPE=en
[root@linux ~]# LC_TIME=en

[root@linux ~]# DATE
-bash: DATE: command not found

[root@linux ~]# cal 13 2005
cal: illegal month value: use 1-12

[root@linux ~]# LANG="en"
# 还记得这个咚咚的用意吧？前面提过了，是为了『语系』的需要啊！下达过一次即可！
[root@linux ~]# man date
DATE(1)                          User Commands                         DATE(1)

NAME
       date - print or set the system date and time

SYNOPSIS
       date [OPTION]... [+FORMAT]
       date [-u|--utc|--universal] [MMDDhhmm[[CC]YY][.ss]]

DESCRIPTION
       Display the current time in the given FORMAT, or set the system date.

       -d, --date=STRING
              display time described by STRING, not 'now'

       -f, --file=DATEFILE
              like --date once for each line of DATEFILE

       -ITIMESPEC, --iso-8601[=TIMESPEC]
              output  date/time  in ISO 8601 format.  TIMESPEC='date' for date
              only, 'hours', 'minutes', or 'seconds' for date and time to  the
              indicated  precision.   --iso-8601  without TIMESPEC defaults to
              'date'.
................(略)....
AUTHOR
       Written by David MacKenzie.

REPORTING BUGS
       Report bugs to .

COPYRIGHT
       Copyright ?2004 Free Software Foundation, Inc.
       This is free software; see the source for copying conditions.  There is
       NO warranty; not even for MERCHANTABILITY or FITNESS FOR  A  PARTICULAR
       PURPOSE.

SEE ALSO
       The  full documentation for date is maintained as a Texinfo manual.  If
       the info and date programs are properly installed  at  your  site,  the
       command

              info coreutils date

       should give you access to the complete manual.

date (coreutils) 5.2.1             May 2005                            DATE(1)

DATE(1)                          User Commands                         DATE(1)

NAME
       date - print or set the system date and time

SYNOPSIS
       date [OPTION]... [+FORMAT]
       date [-u|--utc|--universal] [MMDDhhmm[[CC]YY][.ss]]

DESCRIPTION
       Display the current time in the given FORMAT, or set the system date.

...........(中间省略)........

/date

[root@linux ~]# man -f man
man                  (1)  - format and display the on-line manual pages
man                  (7)  - macros to format man pages
man.conf [man]       (5)  - configuration data for man

[root@linux ~]# man 1 man  <==这里是用 man(1) 的文件数据
[root@linux ~]# man 7 man  <==这里是用 man(7) 的文件数据

[root@linux ~]# man -k man
. [builtins]         (1)  - bash built-in commands, see bash(1)
alias [builtins]     (1)  - bash built-in commands, see bash(1)
........(中间省略)....
xsm                  (1x)  - X Session Manager
zshall               (1)  - the Z shell meta-man page
zshbuiltins          (1)  - zsh built-in commands
zshzle               (1)  - zsh command line editor

[root@linux ~]# whatis  [指令或者是数据]   <==相当于 man -f [指令或者是数据]
[root@linux ~]# apropos [指令或者是数据]   <==相当于 man -k [指令或者是数据]

[root@linux ~]# info info
File: info.info,  Node: Top,  Next: Getting Started,  Up: (dir)

Info: An Introduction
*********************

The GNU Project distributes most of its on-line manuals in the "Info
format", which you read using an "Info reader".  You are probably using
an Info reader to read this now.

   There are two primary Info readers: `info', a stand-alone program
designed just to read Info files, and the `info' package in GNU Emacs,
a general-purpose editor.  At present, only the Emacs reader supports
using a mouse.

   If you are new to the Info reader and want to learn how to use it,
type the command `h' now.  It brings you to a programmed instruction
sequence.

   To read about expert-level Info commands, type `n' twice.  This
brings you to `Info for Experts', skipping over the `Getting Started'
chapter.

* Menu:

* Getting Started::             Getting started using an Info reader.
* Expert Info::                 Info commands for experts.
* Creating an Info File::       How to make your own Info file.
* Index::                       An index of topics, commands, and variables.

--zz-Info: (info.info.gz)Top, 29 lines --All---------------------------------
Welcome to Info version 4.8. Type ? for help, m for menu item.

[root@linux ~]# sync

[root@linux ~]# /sbin/shutdown [-t 秒] [-arkhncfF] [时间] [警告讯息]
实例：
[root@linux ~]# /sbin/shutdown -h 10 'I will shutdown after 10 mins'
告诉大家，这部机器会在十分钟后关机！并且会显示在目前登入者的屏幕前方！
至于参数有哪些呢？以下介绍几个吧！

-t sec  ： -t 后面加秒数，亦即『过几秒后关机』的意思
-k      ： 不要真的关机，只是发送警告讯息出去！
-r      ： 在将系统的服务停掉之后就重新启动
-h      ： 将系统的服务停掉后，立即关机。 
-n      ： 不经过 init 程序，直接以 shutdown 的功能来关机
-f      ： 关机并开机之后，强制略过 fsck 的磁盘检查
-F      ： 系统重新启动之后，强制进行 fsck 的磁盘检查
-c      ： 取消已经在进行的 shutdown 指令内容。

[root@linux ~]# shutdown -h now
立刻关机，其中 now 相当于时间为 0 的状态
[root@linux ~]# shutdown -h 20:25
系统在今天的 20:25 分会关机
[root@linux ~]# shutdown -h +10
系统再过十分钟后自动关机
[root@linux ~]# shutdown -r now
系统立刻重新启动
[root@linux ~]# shutdown -r +30 'The system will reboot' 
再过三十分钟系统会重新启动，并显示后面的讯息。
[root@linux ~]# shutdown -k now 'This system will reboot' 
仅发出警告信件的参数！系统并不会关机啦！吓唬人！

[root@linux ~]# sync; sync; sync; reboot