In command mode and in a procedure, you have the option of determining whether or not a procedure is run, based on conditions specified in an If or While test.
Note: If and While clauses in procedures are different from those in most commands. Rather than controlling which records are processed, If and While, in this context, determine whether or not a procedure is executed. For this reason, using If or While clauses in interactive procedures is not common. Within procedures, If and While clauses are used primarily for conditionally executing one procedure from within another based on conditions determined at run time.
If and While tests can only be specified in command mode or within a procedure.For information on specifying an If or While test, see Do.