Linux variables $ #, $ @, $0, $1, $2, $ *, $, $? Meaning

Linux variables $ #, $ @, $0, $1, $2, $ *, $, $? # Touch variable # vi variable script content :#! /Bin/shecho "number: $ #" echo "scname: $0" echo "first: $1" echo "second: $2" echo "argume: $ @ "echo" show parm list: $ * "echo" show process id: $ "echo" show precomm stat: $? "Save and exit to grant the script execution permission # chmod + x variable to execute the script #. /variable aa bbnumber: 2 scname :. /variablefirst: aasecond: bbargume: aa bbshow parm list: aa bbshow process id: 24544 show precomm stat: 0 you can see through the display result: $ # number of parameters passed to the script $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 $ @ is a list of all parameters passed to the script $ * shows all parameters passed to the script using a single string, different from location variables, a maximum of nine parameters can be set. $ indicates the ID of the current process running the script. $? Is to display the exit status of the last command, 0 indicates there is no error, other indicates there is an error