Perl has so many useful builtins that most people who use the language probably only use a fraction of what's available. Every year or so I like to peruse perlfunc and perlsyn as a refresher. Yet in years and years of hacking Perl code, there are a few in there that I will never use. I surprised myself the other day by reaching for the loop control command redo. It occurred to me that while I use other loop controlling things like next and last constantly, I couldn't remember a single time before when I have ever had to redo an iteration. For the curious, here's the astonishingly simple scenario where it came up.