Shell utility features (summary)

1. Command history:
By pressing the UP ARROW key, you can traverse backward through the most recently entered command under the console, and by pressing the DOWN ARROW key, you can traverse the command you recently entered under the console.
You can also traverse past output in this console with the SHIFT key. You can also edit the old command and then run it.

2. [!$]: Repeat the last parameter of the previous command
Example: [~]# cd/root
[~]# CD!$
[~]# Cd/root

3. Arrangement of commands: (1) use arrange ";" Execute two commands at the same time
                      (2) Use the Arrange "&&" to execute the first command correctly before proceeding to the next command
                      (3) Using piping "|" You can use the output information of the previous command as input to the next command
4.  command alias: syntax: alias [alias]=[Command] Example: # alias ok= "ls-l/boot"   Special instructions: There are spaces in the command, you need to quote.
                   Alias: Syntax: Unalias [Aliases] Example: #unalias ok 
5. Wildcard: "*" can match one or more characters; "?" Can only represent one character.

6. redirect Files 5 ways:
(1) Output redirection, the output of the command command is saved to the file, and if the same file exists, the content command syntax for the file is overwritten: command > File
(2) Enter the redirect, the contents of the file will be the input command syntax of the commands command: command < file
(3) Error redirection, the command command execution error message output to the file in the order syntax: commands 2> file
(4) Append redirect, the output of command command execution is added to the file that already exists. Commands syntax: Order >> file
(5) Simultaneous output and error redirection, the ability to simultaneously implement output redirection and Error redirection commands syntax: command &> file

Shell utility features (summary)