What is the meaning of variable #,@,0,1,2,*,$$,$ in Linux?

$# 是传给脚本的参数个数 $ 0 is the name of the script itself $ 1 is the first parameter passed to the shell script $ 2 is the second parameter passed to the shell script [email protected] is a list of all parameters passed to the script $* is to display all parameters passed to the script in a single string, unlike positional variables, which can exceed the 9 a $$ is the current process ID number for the script to run $? is to display the exit status of the last command, 0 表示没有错误，其他表示有错误

What is the meaning of variable #,@,0,1,2,*,$$,$ in Linux?