Location parameters of Linux shell programming

The positional parameter is a special variant of the shell that is used to pass parameters to the program when running the shell.

$ A indicates the name of the script;

$ $ represents the first argument, the sum is the second argument, and so on, when the number is greater than or equal to 10, it needs to be enclosed in curly braces, such as ${10},${100}.

[Email protected] is the same as $*, which represents the values of all parameters starting from $, separated by spaces.

$ #表示运行程序的时候传入的参数的数目.

$ Indicates the exit status of the program, 0 means no error, and 0 indicates an error.

$$ represents the process number that this script is running on.

Location parameters of Linux shell programming