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

Shell variables in Linux $#, [e-mail protected],$0,$1,$2 meaning explanation:Variable Description: $$ the shell itself PID (ProcessID) $! What is the PID of the Shell's last running background process? End code of the last Run command (return value) $-flag with SET command list $*all parameter lists. As"$*"With""In the case of"$ $ ... $n"all parameters in the form of output. [email protected] all parameter lists. As"[email protected]"With""In the case of"$" "$"... .."$n"all parameters in the form of output. $# the number of arguments added to the shell, the name of the shell itself $1~ $n Each parameter value added to the shell. $ $ is the 1th parameter, and the $ = is the 2nd parameter .... 

Example:1#!/bin/bash2#3 printf"The complete list is%s\n" "$$"4 printf"The complete list is%s\n" "$!"5 printf"The complete list is%s\n" "$?"6 printf"The complete list is%s\n" "$*"7 printf"The complete list is%s\n" "[email protected]"8 printf"The complete list is%s\n" "$#"9 printf"The complete list is%s\n" " $"Ten printf"The complete list is%s\n" " $"printf"The complete list is%s\n" " $

results: [[email protected]~]$ Bash params.sh 123456qqthe complete list is24249The Complete list isThe Complete list is0The complete list is123456qqthe complete list is123456The Complete list isqqthe complete list is2The Complete list isparams.shthe complete list is123456The Complete list isQq

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