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

The meaning of shell variable $#,[email protected],$0,$1,$2 in Linux is explained: Variable Description: $$ The PID of the shell itself (ProcessID) $! PID of the Shell's last running background process $? End code of the last Run command (return value) $- Flag at a glance using the SET command $* All parameter lists. such as "$*" in the Case of "" ", in the form of" $ $ ... $n "output all parameters. [Email protected] All parameter lists. such as "[email protected]" with "" "in the case, with" $ "" $ "... All parameters are output in the form "$n". $# 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/bash  2 #  3 printf "The complete list was%s\n" "$$"  4 printf "The Complete list is%s\n" "$!  " 5 printf "The complete list is%s\n" "$?"  6 printf "The complete list was%s\n" "$*"  7 printf "The Complete list is%s\n" "[email protected]"  8 printf "The C Omplete list is%s\n "" $# "  9 printf" The complete list is%s\n "" $ "printf" The complete list is%s\n "" $ "one pri NTF "The complete list is%s\n" "$

Results:

[Email protected] ~]$ bash params.sh 123456 qqthe complete list are 24249The complete list are the complete list is 0The Co Mplete list is 123456 qqthe complete list are 123456The complete list are qqthe complete list are 2The complete list is param S.shthe complete list are 123456The complete list is QQ

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