This command can be used to request the input of variable values during the
execution of a procedure. When the ASK command is executed, the prompt
will be displayed at the terminal until the requested value is typed in.
If no prompt is given, the command will respond with 'ENTER var_name:'.
Only one value can be requested per ASK command. If you specify a default
value using DEFAULT=def, then this value will be assigned to the variable
if the user enters a carriage return at the prompt.
Examples:
Note that the reply to ASK can be any valid expression.