The if, unless, while and until
statements can be used with a single statement.
They behave the same way as if they were used in the traditional
block form, but in the case where only a single statement is to be
iterated upon, this form can be more readable.
Example:
print "$Result is even\n" if ( ($Result % 2) == 0);
print "$Counter\n" while ($Counter++ < 10);
print "Backup Complete" unless ($Status > 0);
print "Please enter \"QUIT\".\n" until (<STDIN> != "QUIT\n");