Special variables in Shell

Special variables in Shell

 

$0	File Name of the current script
$ N	N is a number starting from 1. $1 represents the first parameter, $2 represents the second parameter, and $ {10} represents the tenth parameter.
$ *	All location parameters (all parameters are used as a string)
$ @	All location parameters (each parameter acts as an independent string)
$ #	Number of input Script Parameters
$ _	Last parameter of the previous command
$?	The Return Value of the previous command. If the previous command is successfully executed, 0 is returned; otherwise, a non-0 value is returned.
$	Pid of the current process
$!	Pid of the last process running in the background
$-	Show options currently used by shell