Solve the problem of document editing in three minutes-[document editing command-cat echo vi / vim tail rmdir]

1. Detailed explanation of cat command

1. Introduction: Display the contents of the file on the terminal
2. Common parameters:

parameter	meaning
-n	Display the number of lines (blank lines are also numbered)
-s	Display the number of lines (multiple blank lines count as one number)
-b	Number of lines displayed (blank lines are not numbered)
-E	$ Symbol at the end of each line
-T	Display TAB characters as ^ I symbols
-v	Use ^ and M- references, except LFD and TAB
-e	Equivalent to "-vE" combination
-t	Equivalent to "-vT" combination
-A	Equivalent to -vET combination
–help	Display help information
–version	Display version information

4. Application examples:

• View the / etc / passwd file and display the file line number
  cat -n /etc/passwd
  
• Use cat to continue writing content into the ./test file until the end of END is encountered
  
• Use cat to write the file as an image file
  cat /dev/fd0 > fdisk.iso

2. Detailed explanation of echo command

1. Introduction:
2. Common parameters:

parameter	meaning
-n	Don't output trailing newline
-it's at"	Sound a warning tone
-e “\b”	Delete the previous character
-e "\ c"	No newline at the end
-e “\f”	Line breaks, the cursor stays at the original coordinate position
-e "\ n"	Line feed, the cursor moves to the beginning of the line
-e “\r”	The cursor moves to the beginning of the line, but does not wrap
-E	Prohibition of backslash transfer, contrary to the function of -e parameter
—version	View version information
–help	View help information

4. Application examples:

• Distinguish the difference between \ f and \ n
  
• Enter the value extracted by the variable into the test file, and enter the date command result

echo $PATH >test
echo `date` >>test
#或者
echo -e "$PATH \n `date`" > test

3. Detailed explanation of vi / vim text editor

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1. Introduction: vi editor is the standard editor of all Linux, used to edit any ASC Ⅱ text, vim is an enhanced version of vi.
2. vi / vim difference

• vi and vim are multi-mode file editors, vim is powerful and vi, vi is a command that comes with linux
• vim supports multi-level undo
• Vim has syntax highlighting, highlighting some files

4. Common parameters:

parameter	meaning
-s	Silent mode
– -Cmd <command>	Execute the specified command before loading any vimrc file
-R	Read-only mode
-v	Vi mode
-e	Ex mode
-and	Easy mode
– --	Only the file name after
-c <command>	加载第一个文件之后执行指定命令
-s<脚本输入文件>	从指定脚本输入文件阅读普通模式命令
-w<脚本输出文件>	追加所有类型的命令写入脚本输出文件
-W<脚本输出文件>	写入所有类型的命令到指定脚本输出文件
+	从文件末尾开始
+<行数>	从指定行开始
– -noplugin	不要加载插件脚本
-p<数量>	打开指定数量的标签页（带文件名）
-r<文件名>	恢复崩溃的会话
-L	等同于-r
-r	列出交换文件并退出
-u	熟用指定vimrc，而不是.vimrc
-T<终端>	设置使用指定终端
-o<数量>	打开指定数量的窗口
-n	不使用交换文件，只用内存
-Z	受限模式
-m	不允许修改（写入）
-b	二进制模式
-M	在文本中不允许修改

4. vim三种模式命令讲解：
   
5. 应用实例讲解：

• 从文件的第5行开始编辑文件
  vim +5 /etc/passwd
  
• 以只读模式打开文件
  vim -R /etc/passwd
  

四、tail 命令详解

1. 简介：用于显示文件尾部的内容，默认在屏幕上显示指定文件的末尾10行。如果给定的文件不止一个，则在显示的每个文件前面加一个文件名标题。如果没有指定文件或者文件名为“-”，则读取标准输入。
2. 常用参数：

参数	含义
- -retry	始终尝试打开文件，常与 -f连接使用
-c 字符数	输出最后指定多少个字符
-f 行数	–follow：显示文件最新追加的内容
-F	与选项“-follow=name”和“–retry”连用时功能相同
-n 行数	输出文件的尾部指定行内容 和-- line=行数效果相同
–pid=<进程号>	与“-f”选项连用，当指定的进程号的进程终止后，自动退出tail命令

4. 应用实例讲解：

#显示文件的最后10行 
tail /etc/passwd
tail -c 10 /etc/passwd
#显示文章从指定行到末尾的内容
tail +20 /etc/passwd
#始终显示文件的最后5行内容
tail -f 5 /test

五、rmdir 命令详解

1. Introduction : The role of the rmdir command is to delete an empty directory, the English full name: "remove directory"
2. Common parameters :

parameter	meaning
-p	Recursively delete all parent directories in the specified directory path, if not empty, an error
-v	Display the detailed execution process of the command

– --Help display the help information of the
command – --version display the version information of the command

4. Application examples:
   recursively delete empty directories and display the process
   rmdir -pv 1/2/3/*