Linux Cloud Automation Fundamentals 4 (System architecture, vim, management input and output, regular expressions)

1. Linux system Architecture
   Linux is an inverted tree structure
   Everything in Linux is a file.
   These files are at the top of the system directory "/"/is the root directory
   /directory Below is a level two directory these directories are automatically created when the system is installed
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2. The role of level two directories
/bin # #二进制可执行文件也就是系统命令
/sbin # #系统管理命令存放位置
/Boot # #启动分区, responsible for system startup
/Dev # #设备管理文件
/etc # #大多数系统管理文件
/Home # #普通用户的家目录
/lib # #32位系统库文件存放位置
/LIB64 # #64位系统库文件存放位置
/media # #系统临时设备挂载点
/MNT # #系统临时设备挂载点
/run # #系统临时设备挂载点
/OPT # #第三方软件安装位置
/proc # #系统信息
/root # #超级用户家目录
/srv,/var # #系统数据
/sys # #系统管理, mostly about the kernel
/tmp # #系统临时文件存放位置
/usr # #系统用户相关信息数据及用户自定义软件存放位置
3. Addressing the file
(1) Absolute path
File in the real location of the system, the file name begins with "/"

(2) Relative path
The file is abbreviated to a name in the current location, and the name does not start with a/, and the name automatically adds the value displayed by the PWD.
4. Regular expressions
(1) wildcard characters
* # # #匹配0到任意字符
？ # # #匹配单个字符
[[: Alpha:]] # # #匹配单个字母
[[: Lower:]] # # #匹配单个小写字母
[[: Upper:]] # # #匹配单个大写字母
[[:d Igit:] # # # #匹配单个数字
[[: Alnum:]] # # #匹配单个数字或字母
[[:p UNCT:] # # # #匹配单个符号
[[: Space:]] # # #匹配单个空格
(2) {} indicates a nonexistent or existing
{1..9} # # #1-9
{A.. F} # # #a-F
{1,3,5} # # #135
{a,c,e} # # #a c E
{1..3} {A.. C} # # #1a 2a 3a 2a 2b 2c 3a 3b 3c multiplication operation

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[] Indicates the existence of the
[A-c] # # #aA BB CC
[A-c] # # #aA或者bB或者c
[1-3] # # #1或者2或者3
[145] # # #1或者4或者5
[^abc]| [!ABC] # # #除了a并且除了b并且除了c

~ # # #当前用户家目录
~username # # #指定的用户家目录
~+ # # #当前目录
~-# # #当前目录之前所在目录

. # # #当前目录
.. # # #当前目录的上一级

1. Managing input and output
   In a Linux system, the standard input is numbered 0, the correct output is numbered 1, and the error output number is 2
   
   Perform "student" with ordinary users in the system
   Find/etc-name passwd
   Because the student user rights issue will have the following output
   Find: '/etc/pki/ca/private ': Permission denied # #没有进入权力, error
   Find: '/etc/pki/rsyslog ': Permission denied
   Find: '/etc/audit ': Permission denied
   /ETC/PASSWD # #正确输出
   Find: '/ETC/POLKIT-1/RULES.D ': Permission denied
   Find: '/etc/polkit-1/localauthority ': Permission denied
   Find: '/etc/dhcp ': Permission denied
   Find: '/etc/selinux/targeted/modules/active ': Permission denied
   Find: '/etc/lvm/archive ': Permission denied
   Find: '/etc/lvm/backup ': Permission denied
   Find: '/etc/lvm/cache ': Permission denied
   Find: '/ETC/GRUB.D ': Permission denied
   /ETC/PAM.D/PASSWD # #正确输出
   Find: '/etc/audisp ': Permission denied
   Find: '/etc/firewalld ': Permission denied
   Find: '/etc/cups/ssl ': Permission denied
   Find: '/etc/ipsec.d ': Permission denied
   Find: '/etc/libvirt ': Permission denied
   Find: '/ETC/SUDOERS.D ': Permission denied
   Find: '/etc/named ': Permission denied
   
   2. (1) Output redirection
   Find/etc-name passwd > File # #重定向正确输出 >

   
   Find/etc-name passwd 2> fi

   Le # #重定向错误输出 2>
   Find/etc-name passwd &> File # #重定向所有输出 &>

2. 
   

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   Note: 2>,&> will overwrite the contents of the source file.
   >file # #清空file
   
   Find/etc-name passwd >> File # #追加正确输出 >>
   Find/etc-name passwd 2>> File # #追加错误输出 2>>
   Find/etc-name passwd &>> File # #追加所有输出 &>>
   Note:>> 2>> &>> does not overwrite the contents of the source file, it will put the corresponding output characters at the end of the file

   
   
   (2) Input redirection: format input to File
   Tr ' A-Z ' A-Z ' < Westos cat > Westos <<eof
   HELLO
   World
   Eof
   
   
   
   3. Pipe symbol: |
   Pipe, the correct output of the previous command as the standard input for the command following the pipe character
   
   Ls/bin | Wc-l # #统计ls

   /bin the number of rows output by the command
   
   The output of the error (STDERR) in the system is not available through the pipeline.
   Use 2>&1 to change the wrong output number from 2 to 1.
   
   Tee copy output to specified location
   Date |tee file |wc-l # # #tee命令复制date命令的输出到file中, and statistics output line

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   4.vim        Command Mode # # # #
   
   (1) in Vim's command mode you can configure how VIM works
   : Set nu            # #行号添加
   : Set nonu        # #取消行号
   : Set mouse=a         # #添加鼠标选择
   : Set cursorline        # #行线显示
   
   The above settings are temporary,
   Permanent settings
   vim/etc/vimrc        ## #此文件为vim的配置文件, at the end of this file add the above parameters, The number of digits added to the file is not required:
   

   
   
   (2). The key word search in vim command mode
   /keyword
   n down match
   N up match
   
   (3). The management of characters in vim command mode
       ( 1. Copying of characters
   yl        # #复制一个字母
   y3l        # #复制3个字母
   yw        # #复制一个单词
   y3w        # #复制3个单词
   yy         # #复制一行
   y3y        # #复制3行
   p        # #复制完成后按 "P" Paste
   
       (2. Deletion of characters
   dl        # #删除一个字母
   d3l        # #删除3个字母
   dw        ## Delete a word
   d3w        # #删除3个单词
   dd        # #删除一行
   d3d        # #删除3行
   

   
   (3. Cutting of characters
   CL # #剪切一个字母
   C3L # #剪切3个字母
   CW # #剪切一个单词
   C3W # #剪切3个单词
   CC # #剪切一行
   C3C # #剪切3行
   ESC---> P # #剪切过后会进入到插入模式, be sure to exit insert mode when performing a paste action
   
   (4). Vim's Visual Mode # # # # # #
   
   Press "CTRL + V" in command mode to enter the visual mode
   In visual mode, you can select characters in the area
   
   Bulk add characters in visual mode
   *>> Ctrl + V Select the column to which you want to add characters
   *>> Press "I" into insert mode, write the characters to be added
   *>> Press ESC
   
   (5). Batch modifier characters # # # #
   
   :%s/original character/replace character # #只替换每一行中出现的第一个原有字符
   :%s/original character/replace character/g # #替换所有
   :%s/^\ *//g # #把全文行首的空格去掉, "^\ *" indicates the space at the beginning of the line

   
   

   
   (6). Vim's split-screen function # # #
   Ctrl+w S # # #上下分屏
   Ctrl+w V # # #左右分屏
   Ctrl+w C # # #关闭光标所在屏幕
   Ctrl+w up or down # # #光标移动到指定屏幕
   : SP File2 # #同时编辑当前文件和file2
   (7). VIM Cursor Movement #####
   in command mode
   : Number # #移动到指定的行
   G # #文件最后一行
   GG # #文件第一行
   
   In insert mode
   I # #光标所在位置插入
   I # #光标所在行行首
   A # #光标所在字符的下一个位置
   A # #光标所在行行尾
   O # #光标所在行下一行
   O # #光标所在行上一行
   S # #删除光标所在字符插入
   S # #删除光标所在行插入
   
   (8). Vim's exit mode
   : Q # #当用vim打开文件但没有对字符作任何操作时可直接退出
   : q! # #当用vim打开文件并对字符作操作, quit all operations
   : Wq # #保存退出
   : wq! # #强行保存退出, effective for Superuser and file owner
   
   (9). Vim Handbook # # # #
   Vimtutor # #vim的手册
   : Q # #退出vimtutor
   
   5.gedit
   

   
   CTRL + N # #在gedit中打开一个新的tab
   Ctrl+s # #保存文件
   Ctrl+o # #打开文件
   Ctrl+x # #剪切字符
   Ctrl + V # #粘贴字符
   CTRL + C # #复制字符
   Yelp Help:gedit # #gedit的图形手册
   
   

This article is from the "13122425" blog, please be sure to keep this source http://13132425.blog.51cto.com/13122425/1950088

Linux Cloud Automation Fundamentals 4 (System architecture, vim, management input and output, regular expressions)