The meaning of shell variable $#,$@,$0,$1,$2 in Linux

printf "The complete list is%s\n" "$$" 24520 the shell itself PID
printf "The complete list is%s\n" "$!" PID of the last running background process of the empty shell
printf "The complete list is%s\n" "$?" 0 end code of the last Run command (return value)
printf "The complete list is%s\n" "$*" 123 all parameters List of QQ. such as "$*" in the Case of "" ", in the form of" $ $ ... $n "output all parameters.
printf "The complete list is%s\n" "[email protected]" 123

printf "The complete list is%s\n" "[Email protected]" 1 QQ all Parameters list. such as "[email protected]" with "" "in the case, with" $ "" $ "... Output all parameters in the form "$n"

printf "The complete list is%s\n" "$#" 2 the number of arguments added to the shell
printf "The complete list is%s\n" "$ 1.shShell" file name of itself
printf "The complete list is%s\n" "$ 123" for each parameter value added to the shell. $ $ is the 1th parameter, and the $ = is the 2nd parameter ...
printf "The complete list is%s\n" "$" QQ

[Email protected] is a list
$* is a whole line of strings.

Linux shell variable $#,[email protected], meaning of $0,$1,$2