>perl -wMstrict -le "my @ra = (9, 8, 7); ;; while (@ra) { print 0+@ra, ' in @ra'; shift @ra; print 0+@ra, ' in @ra'; shift @ra; print 0+@ra, ' in @ra'; shift @ra; print 0+@ra, ' in @ra'; shift @ra; print 0+@ra, ' in @ra'; shift @ra; print 0+@ra, ' in @ra'; } " 3 in @ra 2 in @ra 1 in @ra 0 in @ra 0 in @ra 0 in @ra