Basic knowledge about Linux: a simple shell

Article title: basic knowledge of Linux: simple shell writing. Linux is a technology channel of the IT lab in China. Includes basic categories such as desktop applications, Linux system management, kernel research, embedded systems, and open source.
Script
　　
To create a shell script, you can start by editing an existing shell script. For example, pico writes a script that uses common options to run the tar command to unbind files downloaded from the Internet.
　　
$ Pico untar
　　
Because untar is not saved in the current path, it is created. Then, enter the following content:
　　
#! /Bin/bash
　　
Echo this is the script file $0
　　
Echo untarring the file $1
　　
# Calltar with options-zxvf (filter through gzip, extract, verbose, filename)
　　
Tar-zxvf $1
　　
You can use Key to save, use Key to exit pico.
　　
The first line of the script indicates what shell is used to execute the script. it must start with "#", otherwise it will not be executed. Other rows starting with "#" are comments and won't be executed by shell.
　　
$0, $1, $2... is the parameter passed to the shell script. assume that when you execute the script, the parameters a, B, and c. g are used:
　　
$ Script a B c d e f g
　　
$0 indicates "script", $1 indicates "a", $2 indicates "B", and $3 indicates "c.
　　
The echo function is to echo any information behind it on the screen.
　　
Now, set the file to executable.
　　
$ Chmod u + x untar
　　
This script can be used now. Use the following command to open the my_tar.tar.gz file.
　　
$./Untar my_tar.tar.gz