1.How to populate a variable with random numbers of width 4 characters? Bash shell. What is the shortest possible code?
2.How to display the content of the variable to the user using a for loop. I want to display one character at a time. How to walk through each element in a variable? Bash shell.
3.I want to do data input validation to make sure that the user enters 4 numeric values to my prompt. How to enforce that. Bash shell.