However, lists each argument as a separate word, whereas $* does not distinguish between ordinary spaces separating values and those within quotation marks. echo $* will outputįoobar special variable is similar to $* in that it contains all the values specified as command-line arguments. This special variable contains all the command-line arguments that have been passed to a script, listed as a single word. Consider the example of 'name.sh' there were two parameters passed as 'Sandeep' and ''. The value of this variable is always an integer.

The $# variable contains the total number of parameters entered on the command line. #!/bin/bashī c d e f g h i j b0 Special Variable References $#

The shift command deletes the value of the first variable, and the value of each other variable shifts down and becomes the value of the preceding variable. The value originally at $10 then becomes the value of the $9 variable.įor example, this script – named var.sh – displays the values of the $1 to $10 variables. The third value then replaces the second, and so on. This removes the first parameter's value from the list, and replaces it with the second. To access the value of the $10 variable, you use the shift command. If you try to access the variable $10, the shell interprets $10 as referring to the $1 variable with a following 0 character. Although the shell can access only ten variables simultaneously, you can program scripts to access an unlimited number of items that you specify at the command line. Range of command line argumentsĬommand-line arguments range from $0 to $9. Similarly, the second argument was substituted for the $2. When you executed the above script, the first argument – foobar – was substituted for the $1 variable. Save the above script as 'name.sh' and make it executable by using chmod command as below. #The script demonstrates the use of variables entered at the command line. This is a simple script displays information about a user to understand about script shell argument. The first argument after the script name is assigned to the variable $1, the second argument to $2, and so on. Each script argument entered at the command line has a default variable name. To specify an argument that includes spaces, you need to enclose the complete argument in double quotation marks. The shell automatically assigns each argument name to a variable.Īrguments are set of characters between spaces added after the script.

In a shell script, you can pass variables as arguments by entering arguments after the script name, for example.

Mac shell script example variables