Red Hat® Linux® 7 Unleashed

Positional Parameters

It is possible to write a shell script that takes a number of parameters at the time you invoke it from the command line or from another shell script. These options are supplied to the shell program by Linux as positional parameters, which have special names provided by the system. The first parameter is stored in a variable called 1 (number 1) and can be accessed by using $1 within the program. The second parameter is stored in a variable called 2 and can be accessed by using $2 within the program, and so on. One or more of the higher numbered positional parameters can be omitted while you're invoking a shell program.

For example, if a shell program mypgm expects two parameters--such as a first name and a last name--you ...