On your terminal, type the following command

cal -y 2012

This command would print the calendar for 2012. -y and 2012 are positional parameters. Positional parameters are used to pass arguments to the program. The arguments become available to program as numbered parameters. In the above command, the arguments are passed as follows:

$0 = cal
$1 = -y
$2 = 2012

Following is an example:

#!/bin/bash
#: Title       : positional parameters
#: Date        : 2010-09-22
#: Author      : "Nazim Rahman"
#: Version     : 1.0
#: Description : show how to print and use positional parameters
#: Options     : war and years
#: Example     : $ ./upp.sh WWII 1945
 
printf "Filename: %s\n" "$0"
printf "First Argument: %s\n" "$1"
printf "Second Argument: %s\n" "$2"
printf "%s ended in %s\n" "$1" "$2"

Type the following command to

$ ./upp.sh WWII 1945

Output

Filename: upp.sh
First Argument: WWII
Second Argument: 1945
WWII ended in 1945