1.Linux release has three schools
(1) slackware: SUSE Linux Enterprise Server (SLES) OpenSuse Desktop
(2) Debian: Ubuntu, Mint
(3) RedHat: RedHat Enterprise Linux release every month a new version of
CentOS: The RHEL-compatible format
Kylin: Standard software
Fedora: release a new version every six months
(4) there are some niche version is not listed in the 8111.
Differences between the various distributions:
Debian: Debian Linux is a community-class model, is by far the most followed standard GNU Linux system.
Redhat: domestic use Linux versions of most of the crowd, using the large number of people, information and more, Redhat series of package management is based on the use of YUM package management RPM packages, package distribution methods are compiled binary files.
April 3, 2000 to begin issuing enterprise version of Red Hat Linux 6.2E, regardless of the enterprise version and earlier versions of the home, a unified version. Enterprises with Red Hat Enterprise Linux 2, the consumer version of Fedora 1 (Yarrow).
Links between different releases:
1) All distributions use the Linux kernel.
2) All Linux distributions need to follow the GNU GPL agreement.
3) are basically the same for all Linux distributions naming format.
2、打印显示当前时间，格式是：20181209211008
date +%Y%m%d%H%M%S3, to achieve automatic shutdown 20:30, and prompts the user
shutdown -h 20:30 'I will 20:30 shutdown '
4, summarize the historical command and usage management
history存储曾经使用过的命令，好处是可以重复执行，可以查我干过哪些事，当logout退出时，会把保存
在内存使用过的历史命令写到磁盘中。 Custom history function can be achieved through the environment variable:
HISTSIZE: the number of command history of the shell process can be reserved;
HISTFILE: persistent file command history;
HISTFILESIZE: Command size of the history file;
HISTTIMEFORMAT = "% F% T": show time
HISTIGNORE = "str1: str2: ... ": ignore str1 command history beginning with str2
control command history ways:
environment variables: HISTCONTROL
ignoredups: ignore repeated command;
ignorespace: ignore begins with a blank character command;
ignoreboth: two or more of them to take effect;
erasedups: delete duplicate commands;
modified values of variables:
NAME = 'of vALUE', as HISTCONTROL = ignorespace
login shell, reads command recorded in the history file
~] # cat .bash_history
log into after the new shell command execution will only record in the cache; when the user exits the command "additional" to the command history file
command usage:
history [-c] [-d offset] [the n-]
history -anrw [file name]
history -ps parameter [parameter ...]
-c: Empty command history
-d offset: Delete history specifies that the first command offset
recent history shows that the n: n
-a: append command history list this session of the new Executive to the history file
-n: unread to read the history file line to the history list
-r: reading history file to the history list
-w: save history list to the specified history file
-p: expand the historical parameters into multiple lines, but history list does not exist
-s: expand the historical parameters in a row, appended to the history list
invoke the command history list of commands:
use the ↑ (up) and ↓ (down) keys to navigate up and down the previous command entered
↑: pulls out on command
! #: once again the execution history list Article # command;
:! 0: before executing a command (removal of parameters);
-n:! execution history in the history of the reciprocal of the n-th command;
!!: once again, a command execution;
STRING:! command a recent history list beginning with STRING perform another;
before STRING STRING repeat a command included!?
STRING: print only the p-command history without executing!
: GS / string1! / string2: the previous All command replaces string1 string2
Ctrl + the p-: dug out the previous command;
Ctrl + n: Displays the current history of the next command, but does not perform;
Ctrl + J: execution of the current command;
Ctrl + r: be in command history search command
Ctrl + g: Exit from the history search mode
a command on call the last parameter:
the string:! $
shortcut: press ESC, and then press.
Alt + (hold down the Alt key while clicking button.).
$:! the p-: $ printout (the last argument on a command)! content
:! p: printout (all parameters on a command) of content!
5、总结Linux帮助用法
whatis 简要的告诉这个命令的功能，当刚安装上系统时，whatis数据库是没有的。过一段时间自己可以生成，
使用makewhatis创建这个数据库（centos6），centos7使用mandb命令，whatis等价与man -f。
例：whatis rm
查看内部帮助命令用help，help本身是一个内部命令。
COMMAND --helpCOMMAND -h
info是将文件数据拆成一个一个的段落，每个段落用自己的页面来编写，并且在各个页面中还有类似网页的
超链接来跳到各个不同的页面中，每个独立的页面也被称作韦一个节点。info related commands:
The key role of
the arrow keys, PgUp, PgDn navigation
Tab key to move to the next link
d show theme directory
b, Ctrl + b scroll the file header
Home display subject header
Enter into the selected link
n / p / u / l The entry / front level / last link / on
s literal text search
q quit info
man related to the operation command summary:
Key role
Space turning down a
Page Down scroll down a
Page Up turned upward a
b, Ctrl + b flipping the header file
u, Ctrl + u turned half screen to a file header
d, Ctrl + d to the end of the file Total half screen
y, k row to turn header files
e, j to the end of the file line turned
HOME directly to home
END End directly to
1G file header Back
G turn to the end of the file
#G # jumps to the first row
/ keyword from a file in order to find the head end of the file (not case sensitive characters)
? keyword in order to find the header files from the end of the file
n the same direction with the Find command
N with the Find command in the opposite direction
q to exit the help documentation